{"segment":[{"time":24,"part":[{"title":"\u0110i\u1ec1n s\u1ed1 th\u00edch h\u1ee3p v\u00e0o ch\u1ed7 tr\u1ed1ng","title_trans":"","temp":"fill_the_blank","correct":[[["-79"]]],"list":[{"point":5,"width":60,"type_input":"","ques":"<center><img src='https://www.luyenthi123.com/file/luyenthi123/lop6/toan/daiso/bai24/lv2/img\/2.jpg' \/><\/center> 3752 - (29 + 3752) - 50 = _input_","hint":"","explain":"<span class='basic_left'><span class='basic_green'>H\u01b0\u1edbng d\u1eabn:<\/span><br\/> Thay \u0111\u1ed5i v\u1ecb tr\u00ed s\u1ed1 h\u1ea1ng v\u00e0 b\u1ecf ho\u1eb7c \u0111\u1eb7t d\u1ea5u ngo\u1eb7c m\u1ed9t c\u00e1ch th\u00edch h\u1ee3p r\u1ed3i t\u00ednh<br\/><b>L\u01b0u \u00fd: <\/b><br\/>+ Khi b\u1ecf d\u1ea5u ngo\u1eb7c c\u00f3 d\u1ea5u (-) \u0111\u1eb1ng tr\u01b0\u1edbc, ta ph\u1ea3i \u0111\u1ed5i t\u1ea5t c\u1ea3 c\u00e1c s\u1ed1 h\u1ea1ng trong d\u1ea5u ngo\u1eb7c: d\u1ea5u ( + ) th\u00e0nh d\u1ea5u ( - ) v\u00e0 d\u1ea5u ( - ) th\u00e0nh d\u1ea5u ( + )<br\/>+ Khi b\u1ecf d\u1ea5u ngo\u1eb7c c\u00f3 d\u1ea5u ( + ) \u0111\u1eb1ng tr\u01b0\u1edbc th\u00ec d\u1ea5u c\u00e1c s\u1ed1 h\u1ea1ng trong ngo\u1eb7c v\u1eabn gi\u1eef nguy\u00ean.<\/span> <br\/><br\/><span class='basic_green'>B\u00e0i gi\u1ea3i:<\/span><br\/>$\\begin{align*}3752 - (29 + 3752) - 50 &= 3752 - 29 - 3752 - 50\\\\&= (3752 - 3752) - (29 + 50)\\\\&= 0 - 79\\\\&= -79\\end{align*}$<br\/>V\u1eady s\u1ed1 c\u1ea7n \u0111i\u1ec1n v\u00e0o \u00f4 tr\u1ed1ng l\u00e0: <span class='basic_pink'> -79<\/span><\/span> <br\/> "}]}],"id_ques":1161},{"time":24,"part":[{"title":"\u0110i\u1ec1n s\u1ed1 th\u00edch h\u1ee3p v\u00e0o ch\u1ed7 tr\u1ed1ng","title_trans":"","temp":"fill_the_blank","correct":[[["8335","+8335"]]],"list":[{"point":5,"width":60,"type_input":"","ques":"<center><img src='https://www.luyenthi123.com/file/luyenthi123/lop6/toan/daiso/bai24/lv2/img\/2.jpg' \/><\/center> 9415 - (1381 - 142) - (-159) = _input_","hint":"","explain":"<span class='basic_left'><span class='basic_green'>H\u01b0\u1edbng d\u1eabn:<\/span><br\/> Thay \u0111\u1ed5i v\u1ecb tr\u00ed s\u1ed1 h\u1ea1ng v\u00e0 b\u1ecf ho\u1eb7c \u0111\u1eb7t d\u1ea5u ngo\u1eb7c m\u1ed9t c\u00e1ch th\u00edch h\u1ee3p r\u1ed3i t\u00ednh<br\/><b>L\u01b0u \u00fd: <\/b><br\/>+ Khi b\u1ecf d\u1ea5u ngo\u1eb7c c\u00f3 d\u1ea5u (-) \u0111\u1eb1ng tr\u01b0\u1edbc, ta ph\u1ea3i \u0111\u1ed5i t\u1ea5t c\u1ea3 c\u00e1c s\u1ed1 h\u1ea1ng trong d\u1ea5u ngo\u1eb7c: d\u1ea5u ( + ) th\u00e0nh d\u1ea5u ( - ) v\u00e0 d\u1ea5u ( - ) th\u00e0nh d\u1ea5u ( + )<br\/>+ Khi b\u1ecf d\u1ea5u ngo\u1eb7c c\u00f3 d\u1ea5u ( + ) \u0111\u1eb1ng tr\u01b0\u1edbc th\u00ec d\u1ea5u c\u00e1c s\u1ed1 h\u1ea1ng trong ngo\u1eb7c v\u1eabn gi\u1eef nguy\u00ean.<\/span> <br\/><br\/><span class='basic_green'>B\u00e0i gi\u1ea3i:<\/span><br\/>$\\begin{align*}9415 - (1381 - 142) - (-159) &= 9415 - 1239 + 159\\\\&= 8176 + 159\\\\&= 8335\\end{align*}$<br\/>V\u1eady s\u1ed1 c\u1ea7n \u0111i\u1ec1n v\u00e0o \u00f4 tr\u1ed1ng l\u00e0: <span class='basic_pink'> 8335<\/span><\/span> <br\/> "}]}],"id_ques":1162},{"time":24,"part":[{"title":"\u0110i\u1ec1n s\u1ed1 th\u00edch h\u1ee3p v\u00e0o ch\u1ed7 tr\u1ed1ng","title_trans":"","temp":"fill_the_blank","correct":[[["2008","+2008"]]],"list":[{"point":5,"width":60,"type_input":"","ques":" T\u00ednh nhanh: <br\/>(117 + 2133) + (2008 - 117 - 2133)= _input_","hint":"","explain":"<span class='basic_left'><span class='basic_green'>H\u01b0\u1edbng d\u1eabn:<\/span><br\/> B\u1ecf ngo\u1eb7c r\u1ed3i nh\u00f3m c\u1eb7p s\u1ed1 c\u00f3 t\u1ed5ng ho\u1eb7c hi\u1ec7u b\u1eb1ng 0 hay l\u00e0 s\u1ed1 tr\u00f2n ch\u1ee5c, tr\u00f2n tr\u0103m, tr\u00f2n ngh\u00ecn... \u0111\u1ec3 th\u1ef1c hi\u1ec7n t\u00ednh nhanh.<br\/><b>L\u01b0u \u00fd: <\/b><br\/>+ Khi b\u1ecf d\u1ea5u ngo\u1eb7c c\u00f3 d\u1ea5u (-) \u0111\u1eb1ng tr\u01b0\u1edbc, ta ph\u1ea3i \u0111\u1ed5i t\u1ea5t c\u1ea3 c\u00e1c s\u1ed1 h\u1ea1ng trong d\u1ea5u ngo\u1eb7c: d\u1ea5u ( + ) th\u00e0nh d\u1ea5u ( - ) v\u00e0 d\u1ea5u ( - ) th\u00e0nh d\u1ea5u ( + )<br\/>+ Khi b\u1ecf d\u1ea5u ngo\u1eb7c c\u00f3 d\u1ea5u ( + ) \u0111\u1eb1ng tr\u01b0\u1edbc th\u00ec d\u1ea5u c\u00e1c s\u1ed1 h\u1ea1ng trong ngo\u1eb7c v\u1eabn gi\u1eef nguy\u00ean.<\/span> <br\/><br\/><span class='basic_left'><span class='basic_green'>B\u00e0i gi\u1ea3i:<\/span><br\/>$\\begin{align*}(117 + 2133) + (2008 - 117 - 2133) &= 117 + 2133 + 2008 - 117 - 2133 \\\\&= (117 - 117) + (2133 - 2133) + 2008\\\\&= 0 + 0 + 2008\\\\&= 2008\\end{align*}$<br\/>V\u1eady s\u1ed1 c\u1ea7n \u0111i\u1ec1n v\u00e0o \u00f4 tr\u1ed1ng l\u00e0: <span class='basic_pink'> 2008<\/span><\/span> <br\/> "}]}],"id_ques":1163},{"time":24,"part":[{"title":"\u0110i\u1ec1n s\u1ed1 th\u00edch h\u1ee3p v\u00e0o ch\u1ed7 tr\u1ed1ng","title_trans":"","temp":"fill_the_blank","correct":[[["-6"]]],"list":[{"point":5,"width":60,"type_input":"","ques":" T\u00ednh nhanh: <br\/>(1930 - 3 - 2) - (3 - 2 + 1930) = _input_","hint":"","explain":"<span class='basic_left'><span class='basic_green'>H\u01b0\u1edbng d\u1eabn:<\/span><br\/> B\u1ecf ngo\u1eb7c r\u1ed3i nh\u00f3m c\u1eb7p s\u1ed1 c\u00f3 t\u1ed5ng ho\u1eb7c hi\u1ec7u b\u1eb1ng 0 hay l\u00e0 s\u1ed1 tr\u00f2n ch\u1ee5c, tr\u00f2n tr\u0103m, tr\u00f2n ngh\u00ecn... \u0111\u1ec3 th\u1ef1c hi\u1ec7n t\u00ednh nhanh.<br\/><b>L\u01b0u \u00fd: <\/b><br\/>+ Khi b\u1ecf d\u1ea5u ngo\u1eb7c c\u00f3 d\u1ea5u (-) \u0111\u1eb1ng tr\u01b0\u1edbc, ta ph\u1ea3i \u0111\u1ed5i t\u1ea5t c\u1ea3 c\u00e1c s\u1ed1 h\u1ea1ng trong d\u1ea5u ngo\u1eb7c: d\u1ea5u ( + ) th\u00e0nh d\u1ea5u ( - ) v\u00e0 d\u1ea5u ( - ) th\u00e0nh d\u1ea5u ( + )<br\/>+ Khi b\u1ecf d\u1ea5u ngo\u1eb7c c\u00f3 d\u1ea5u ( + ) \u0111\u1eb1ng tr\u01b0\u1edbc th\u00ec d\u1ea5u c\u00e1c s\u1ed1 h\u1ea1ng trong ngo\u1eb7c v\u1eabn gi\u1eef nguy\u00ean.<\/span> <br\/><br\/><span class='basic_left'><span class='basic_green'>B\u00e0i gi\u1ea3i:<\/span><br\/>$\\begin{align*}(1930 - 3 - 2) - (3 - 2 + 1930) &= 1930 - 3 - 2 - 3 + 2 - 1930 \\\\&= (1930 - 1930) + (2 - 2) - (3 + 3)\\\\&= 0 + 0 - 6\\\\&= -6\\end{align*}$<br\/>V\u1eady s\u1ed1 c\u1ea7n \u0111i\u1ec1n v\u00e0o \u00f4 tr\u1ed1ng l\u00e0: <span class='basic_pink'> -6<\/span><\/span> <br\/> <span class='basic_left'><span class='basic_green'>Nh\u1eadn x\u00e9t:<\/span> <br\/>Trong m\u1ed9t t\u1ed5ng \u0111\u1ea1i s\u1ed1, ta c\u00f3 th\u1ec3: \u0111\u1eb7t d\u1ea5u ngo\u1eb7c \u0111\u1ec3 nh\u00f3m c\u00e1c s\u1ed1 h\u1ea1ng m\u1ed9t c\u00e1ch t\u00f9y \u00fd v\u1edbi ch\u00fa \u00fd r\u1eb1ng n\u1ebfu tr\u01b0\u1edbc d\u1ea5u ngo\u1eb7c l\u00e0 d\u1ea5u ( - ) th\u00ec ph\u1ea3i \u0111\u1ed1i d\u1ea5u t\u1ea5t c\u1ea3 c\u00e1c s\u1ed1 h\u1ea1ng trong ngo\u1eb7c<br\/><b>V\u00ed d\u1ee5: a - b - c = a - (b + c)<\/b><\/span><\/span> "}]}],"id_ques":1164},{"time":24,"part":[{"title":"L\u1ef1a ch\u1ecdn \u0111\u00e1p \u00e1n \u0111\u00fang nh\u1ea5t","title_trans":"","temp":"multiple_choice","correct":[[1]],"list":[{"point":5,"ques":" B\u1ecf ngo\u1eb7c r\u1ed3i t\u00ednh: <br\/>-35 + 20 - [-8 - (-37)] = <span class='basic_hoi_black'>?<\/span>","select":["A. -44","B. 30","C. 44","D. 14"],"hint":"","explain":" <span class='basic_left'><span class='basic_green'>H\u01b0\u1edbng d\u1eabn:<\/span><br\/> B\u1ecf d\u1ea5u ngo\u1eb7c r\u1ed3i th\u1ef1c hi\u1ec7n t\u00ednh<br\/><b>L\u01b0u \u00fd: <\/b><br\/>+ Khi b\u1ecf d\u1ea5u ngo\u1eb7c c\u00f3 d\u1ea5u (-) \u0111\u1eb1ng tr\u01b0\u1edbc, ta ph\u1ea3i \u0111\u1ed5i t\u1ea5t c\u1ea3 c\u00e1c s\u1ed1 h\u1ea1ng trong d\u1ea5u ngo\u1eb7c: d\u1ea5u ( + ) th\u00e0nh d\u1ea5u ( - ) v\u00e0 d\u1ea5u ( - ) th\u00e0nh d\u1ea5u ( + )<br\/>+ Khi b\u1ecf d\u1ea5u ngo\u1eb7c c\u00f3 d\u1ea5u ( + ) \u0111\u1eb1ng tr\u01b0\u1edbc th\u00ec d\u1ea5u c\u00e1c s\u1ed1 h\u1ea1ng trong ngo\u1eb7c v\u1eabn gi\u1eef nguy\u00ean.<\/span> <br\/><br\/><span class='basic_green'>B\u00e0i gi\u1ea3i:<\/span><br\/>$\\begin{align*}-35 + 20 - [-8 - (-37)] &= -15 - (-8 + 37)\\\\&= -15 + 8 - 37 \\\\&= -7 - 37\\\\&= - (7 + 37)\\\\&= -44\\end{align*}$<br\/>V\u1eady ta ch\u1ecdn \u0111\u00e1p \u00e1n \u0111\u00fang l\u00e0: <span class='basic_pink'> A. -44<\/span><\/span> <br\/>","column":2}]}],"id_ques":1165},{"time":24,"part":[{"title":"L\u1ef1a ch\u1ecdn \u0111\u00e1p \u00e1n \u0111\u00fang nh\u1ea5t","title_trans":"","temp":"multiple_choice","correct":[[3]],"list":[{"point":5,"ques":" B\u1ecf ngo\u1eb7c r\u1ed3i t\u00ednh: <br\/> (-9) + (-10) - [-8 - (-11)] = <span class='basic_hoi_black'>?<\/span>","select":["A. -16","B. 22","C. -22","D. 0"],"hint":"","explain":" <span class='basic_left'><span class='basic_green'>H\u01b0\u1edbng d\u1eabn:<\/span><br\/> B\u1ecf d\u1ea5u ngo\u1eb7c r\u1ed3i th\u1ef1c hi\u1ec7n t\u00ednh<br\/><b>L\u01b0u \u00fd: <\/b><br\/>+ Khi b\u1ecf d\u1ea5u ngo\u1eb7c c\u00f3 d\u1ea5u (-) \u0111\u1eb1ng tr\u01b0\u1edbc, ta ph\u1ea3i \u0111\u1ed5i t\u1ea5t c\u1ea3 c\u00e1c s\u1ed1 h\u1ea1ng trong d\u1ea5u ngo\u1eb7c: d\u1ea5u ( + ) th\u00e0nh d\u1ea5u ( - ) v\u00e0 d\u1ea5u ( - ) th\u00e0nh d\u1ea5u ( + )<br\/>+ Khi b\u1ecf d\u1ea5u ngo\u1eb7c c\u00f3 d\u1ea5u ( + ) \u0111\u1eb1ng tr\u01b0\u1edbc th\u00ec d\u1ea5u c\u00e1c s\u1ed1 h\u1ea1ng trong ngo\u1eb7c v\u1eabn gi\u1eef nguy\u00ean.<\/span> <br\/><br\/><span class='basic_green'>B\u00e0i gi\u1ea3i:<\/span><br\/>$\\begin{align*}(-9) + (-10) - [-8 - (-11)] &= -9 - 10 + 8 + (-11)\\\\&= -9 - 10 + 8 - 11 \\\\&= - (9 + 11 + 10) + 8\\\\&= - 30 + 8\\\\&= -22\\end{align*}$<br\/>V\u1eady ta ch\u1ecdn \u0111\u00e1p \u00e1n \u0111\u00fang l\u00e0: <span class='basic_pink'> C. -22<\/span><\/span> <br\/>","column":2}]}],"id_ques":1166},{"time":24,"part":[{"title":"L\u1ef1a ch\u1ecdn \u0111\u00e1p \u00e1n \u0111\u00fang nh\u1ea5t","title_trans":"","temp":"multiple_choice","correct":[[1]],"list":[{"point":5,"ques":" T\u00ecm x, bi\u1ebft:<br\/>(-14) + x - 7 = -10","select":["A. x = 11","B. x = -11","C. x = 31","D. x = -31"],"hint":"","explain":" <span class='basic_left'><span class='basic_green'>H\u01b0\u1edbng d\u1eabn:<\/span><br\/> <b>+ C\u00e1ch 1: <\/b><br\/>B\u01b0\u1edbc 1: Thu g\u1ecdn v\u1ebf tr\u00e1i<br\/>B\u01b0\u1edbc 2: T\u00ecm x<br\/><b>+ C\u00e1ch 2:<\/b><br\/>Coi (-14) + x l\u00e0 s\u1ed1 b\u1ecb tr\u1eeb, mu\u1ed1n t\u00ecm s\u1ed1 b\u1ecb tr\u1eeb ta l\u1ea5y hi\u1ec7u c\u1ed9ng v\u1edbi s\u1ed1 tr\u1eeb.<\/span> <br\/><br\/><span class='basic_left'><span class='basic_green'>B\u00e0i gi\u1ea3i:<\/span><br\/><b>C\u00e1ch 1:<\/b><br\/>$\\begin{align*}(-14) + x - 7 &= -10\\\\x - (14 + 7)&= -10 \\\\x - 21&= -10\\\\x&= -10 + 21\\\\x&= 21 - 10\\\\x&= 11\\end{align*}$<br\/><b> C\u00e1ch 2:<\/b><br\/> $\\begin{align*}(-14) + x - 7 &= -10\\\\(-14) + x &= (-10) + 7 \\\\(-14) + x&= -3\\\\x&= -3 - (-14)\\\\x&= -3 + 14\\\\x&= 11\\end{align*}$<br\/>V\u1eady ta ch\u1ecdn \u0111\u00e1p \u00e1n \u0111\u00fang l\u00e0: <span class='basic_pink'> A. x = 11<\/span><\/span> <br\/><\/span>","column":2}]}],"id_ques":1167},{"time":24,"part":[{"title":"L\u1ef1a ch\u1ecdn \u0111\u00e1p \u00e1n \u0111\u00fang nh\u1ea5t","title_trans":"","temp":"multiple_choice","correct":[[1]],"list":[{"point":5,"ques":" T\u00ecm x, bi\u1ebft:<br\/>(-14) - x + (-15) = -10","select":["A. x = -19","B. x = 19","C. x = 39","D. x = -39"],"hint":"","explain":" <span class='basic_left'><span class='basic_green'>H\u01b0\u1edbng d\u1eabn:<\/span><br\/> <b>+ C\u00e1ch 1: <\/b><br\/>B\u01b0\u1edbc 1: Thu g\u1ecdn v\u1ebf tr\u00e1i<br\/>B\u01b0\u1edbc 2: T\u00ecm x<br\/><b>+ C\u00e1ch 2:<\/b><br\/>Coi (-14) - x l\u00e0 s\u1ed1 h\u1ea1ng, mu\u1ed1n t\u00ecm s\u1ed1 h\u1ea1ng ch\u01b0a bi\u1ebft ta l\u1ea5y t\u1ed5ng tr\u1eeb \u0111i s\u1ed1 h\u1ea1ng \u0111\u00e3 bi\u1ebft<\/span> <br\/><br\/><span class='basic_left'><span class='basic_green'>B\u00e0i gi\u1ea3i:<\/span><br\/><b>C\u00e1ch 1:<\/b><br\/>$\\begin{align*}(-14) - x + (-15) &= -10\\\\- (14 + 15) - x&= -10 \\\\-29 - x&= -10\\\\x&= -29 - (-10)\\\\x&= -29 + 10\\\\x&= -19\\end{align*}$<br\/><b> C\u00e1ch 2:<\/b><br\/> $\\begin{align*}(-14) - x + (-15) &= -10\\\\(-14) - x &= (-10) - (-15) \\\\(-14) - x&= -10 + 15\\\\-14 - x&= 5\\\\x&= -14 - 5\\\\x&= - (4 + 15)\\\\x&= -19\\end{align*}$<br\/>V\u1eady ta ch\u1ecdn \u0111\u00e1p \u00e1n \u0111\u00fang l\u00e0: <span class='basic_pink'> A. x = -19<\/span><\/span> <br\/><\/span>","column":2}]}],"id_ques":1168},{"time":24,"part":[{"title":"L\u1ef1a ch\u1ecdn \u0111\u00e1p \u00e1n \u0111\u00fang nh\u1ea5t","title_trans":"","temp":"multiple_choice","correct":[[1]],"list":[{"point":5,"ques":" Thu g\u1ecdn bi\u1ec3u th\u1ee9c:<br\/> A = (x - 47) - (x + 59 - 81) + 35 - x","select":["A = -x + 10","A = -x - 34","A = 128 - x","A = x + 10"],"hint":" ","explain":" <span class='basic_left'><span class='basic_green'>H\u01b0\u1edbng d\u1eabn:<\/span><br\/> B\u1ecf d\u1ea5u ngo\u1eb7c r\u1ed3i th\u1ef1c hi\u1ec7n thu g\u1ecdn<br\/><b>L\u01b0u \u00fd: <\/b><br\/>+ Khi b\u1ecf d\u1ea5u ngo\u1eb7c c\u00f3 d\u1ea5u (-) \u0111\u1eb1ng tr\u01b0\u1edbc, ta ph\u1ea3i \u0111\u1ed5i t\u1ea5t c\u1ea3 c\u00e1c s\u1ed1 h\u1ea1ng trong d\u1ea5u ngo\u1eb7c: d\u1ea5u ( + ) th\u00e0nh d\u1ea5u ( - ) v\u00e0 d\u1ea5u ( - ) th\u00e0nh d\u1ea5u ( + )<br\/>+ Khi b\u1ecf d\u1ea5u ngo\u1eb7c c\u00f3 d\u1ea5u ( + ) \u0111\u1eb1ng tr\u01b0\u1edbc th\u00ec d\u1ea5u c\u00e1c s\u1ed1 h\u1ea1ng trong ngo\u1eb7c v\u1eabn gi\u1eef nguy\u00ean.<\/span> <br\/><br\/><span class='basic_green'>B\u00e0i gi\u1ea3i:<\/span><br\/><br\/>$\\begin{align*}A &= (x - 47) - (x + 59 - 81) + 35 - x \\\\A&= x - 47 - x - 59 + 81 + 35 - x\\\\A&= (x - x) - x + (81 + 35 - 47 - 59) \\\\A&= 0 - x + (116 - 47 - 59)\\\\A&= -x + (69 - 59)\\\\A&= - x + 10\\end{align*}$<br\/>V\u1eady ta ch\u1ecdn \u0111\u00e1p \u00e1n \u0111\u00fang l\u00e0: <span class='basic_pink'> A = -x + 10<\/span><\/span> <br\/>","column":2}]}],"id_ques":1169},{"time":24,"part":[{"title":"L\u1ef1a ch\u1ecdn \u0111\u00e1p \u00e1n \u0111\u00fang nh\u1ea5t","title_trans":"","temp":"multiple_choice","correct":[[2]],"list":[{"point":5,"ques":" Thu g\u1ecdn bi\u1ec3u th\u1ee9c:<br\/> A = (102 - 15) - (15 - x) + (48 - 3)","select":["A = -x + 123","A = x + 117","A = x + 123","A = x + 147"],"hint":" ","explain":" <span class='basic_left'><span class='basic_green'>H\u01b0\u1edbng d\u1eabn:<\/span><br\/> Th\u1ef1c hi\u1ec7n t\u00ednh c\u00e1c ph\u00e9p t\u00ednh trong ngo\u1eb7c tr\u01b0\u1edbc r\u1ed3i b\u1ecf ngo\u1eb7c ph\u00e9p t\u00ednh ch\u1ee9a \u1ea9n \u0111\u1ec3 thu g\u1ecdn bi\u1ec3u th\u1ee9c.<br\/><b>L\u01b0u \u00fd: <\/b><br\/>+ Khi b\u1ecf d\u1ea5u ngo\u1eb7c c\u00f3 d\u1ea5u (-) \u0111\u1eb1ng tr\u01b0\u1edbc, ta ph\u1ea3i \u0111\u1ed5i t\u1ea5t c\u1ea3 c\u00e1c s\u1ed1 h\u1ea1ng trong d\u1ea5u ngo\u1eb7c: d\u1ea5u ( + ) th\u00e0nh d\u1ea5u ( - ) v\u00e0 d\u1ea5u ( - ) th\u00e0nh d\u1ea5u ( + )<br\/>+ Khi b\u1ecf d\u1ea5u ngo\u1eb7c c\u00f3 d\u1ea5u ( + ) \u0111\u1eb1ng tr\u01b0\u1edbc th\u00ec d\u1ea5u c\u00e1c s\u1ed1 h\u1ea1ng trong ngo\u1eb7c v\u1eabn gi\u1eef nguy\u00ean.<\/span> <br\/><br\/><span class='basic_green'>B\u00e0i gi\u1ea3i:<\/span><br\/><br\/>$\\begin{align*}A &= (102 - 15) - (15 - x) + (48 - 3) \\\\A&= 87 - 15 + x + 45\\\\A&= x + (45 - 15 + 87) \\\\A&= x + (30 + 87)\\\\A&= x + 117\\end{align*}$<br\/>V\u1eady ta ch\u1ecdn \u0111\u00e1p \u00e1n \u0111\u00fang l\u00e0: <span class='basic_pink'> A = x + 117<\/span><\/span> <br\/>","column":2}]}],"id_ques":1170},{"time":24,"part":[{"title":"L\u1ef1a ch\u1ecdn \u0111\u00e1p \u00e1n \u0111\u00fang nh\u1ea5t","title_trans":"","temp":"multiple_choice","correct":[[1]],"list":[{"point":5,"ques":" T\u00ednh t\u1ed5ng c\u00e1c s\u1ed1 nguy\u00ean x, bi\u1ebft: -3 $\\le$ x < 4 ","select":["A. 0","B. -3 ","C. -4","D. 4"],"hint":"","explain":" <span class='basic_left'><span class='basic_green'>H\u01b0\u1edbng d\u1eabn:<\/span><br\/>B\u01b0\u1edbc 1: T\u00ecm c\u00e1c s\u1ed1 nguy\u00ean x th\u1ecfa m\u00e3n -3 $\\le$ x < 4<br\/>B\u01b0\u1edbc 2: T\u00ednh t\u1ed5ng c\u00e1c s\u1ed1 nguy\u00ean x v\u1eeba t\u00ecm \u0111\u01b0\u1ee3c \u1edf b\u01b0\u1edbc 1<br\/><\/span> <br\/><br\/><span class='basic_left'> <span class='basic_green'>B\u00e0i gi\u1ea3i:<\/span><br\/>Ta c\u00f3: -3 $\\le$ x < 4 $\\Rightarrow $ x $ \\in$ { -3; -2; -1; 0; 1; 2; 3}<br\/> T\u1ed5ng c\u1ee7a c\u00e1c s\u1ed1 nguy\u00ean x l\u00e0:<br\/>$\\begin{align*}&(-3) + (-2) + (-1) + 0 + 1 + 2 + 3 \\\\&= -3 - 2 - 1 + 0 + 1 + 2 + 3 \\\\&= (3 - 3) + ( 2 - 2) + (1 - 1) + 0\\\\&= 0 + 0 + 0 + 0\\\\&= 0\\end{align*}$<br\/>V\u1eady ta ch\u1ecdn \u0111\u00e1p \u00e1n \u0111\u00fang l\u00e0: <span class='basic_pink'> A. 0<\/span><\/span><\/span> <br\/>","column":2}]}],"id_ques":1171},{"time":24,"part":[{"title":"L\u1ef1a ch\u1ecdn \u0111\u00e1p \u00e1n \u0111\u00fang nh\u1ea5t","title_trans":"","temp":"multiple_choice","correct":[[3]],"list":[{"point":5,"ques":" T\u00ednh t\u1ed5ng c\u00e1c s\u1ed1 nguy\u00ean x, bi\u1ebft: -4 $\\le$ x < 4 ","select":["A. 0","B. -3 ","C. -4","D. 4"],"hint":"","explain":" <span class='basic_left'><span class='basic_green'>H\u01b0\u1edbng d\u1eabn:<\/span><br\/>B\u01b0\u1edbc 1: T\u00ecm c\u00e1c s\u1ed1 nguy\u00ean x th\u1ecfa m\u00e3n -4 $\\le$ x < 4 <br\/>B\u01b0\u1edbc 2: T\u00ednh t\u1ed5ng c\u00e1c s\u1ed1 nguy\u00ean x v\u1eeba t\u00ecm \u0111\u01b0\u1ee3c \u1edf b\u01b0\u1edbc 1<br\/><\/span> <br\/><br\/><span class='basic_left'> <span class='basic_green'>B\u00e0i gi\u1ea3i:<\/span><br\/>Ta c\u00f3: -4 $\\le$ x < 4 $\\Rightarrow $ x $ \\in$ { -4; -3; -2; -1; 0; 1; 2; 3}<br\/> T\u1ed5ng c\u1ee7a c\u00e1c s\u1ed1 nguy\u00ean x l\u00e0:<br\/>$\\begin{align*}&(-4) + (-3) + (-2) + (-1) + 0 + 1 + 2 + 3 \\\\&= -4 -3 - 2 - 1 + 0 + 1 + 2 + 3 \\\\&= (-4) + (3 - 3) + ( 2 - 2) + (1 - 1) + 0\\\\&= (-4) + 0 + 0 + 0 + 0\\\\&= -4\\end{align*}$<br\/>V\u1eady ta ch\u1ecdn \u0111\u00e1p \u00e1n \u0111\u00fang l\u00e0: <span class='basic_pink'> C. -4<\/span><\/span><\/span> <br\/>","column":2}]}],"id_ques":1172},{"time":24,"part":[{"title":"L\u1ef1a ch\u1ecdn \u0111\u00e1p \u00e1n \u0111\u00fang nh\u1ea5t","title_trans":"","temp":"multiple_choice","correct":[[3]],"list":[{"point":5,"ques":" B\u1ecf ngo\u1eb7c bi\u1ec3u th\u1ee9c: -80 - [-34 - (-15)] = <span class='basic_hoi_black'>?<\/span>","select":["A. -80 + 34 + 15","B. -80 - 34 + 15","C. -80 + 34 - 15","D. -80 - 34 - 15"],"hint":"","explain":" <span class='basic_left'><span class='basic_green'>H\u01b0\u1edbng d\u1eabn:<\/span><br\/> + Khi b\u1ecf d\u1ea5u ngo\u1eb7c c\u00f3 d\u1ea5u (-) \u0111\u1eb1ng tr\u01b0\u1edbc, ta ph\u1ea3i \u0111\u1ed5i t\u1ea5t c\u1ea3 c\u00e1c s\u1ed1 h\u1ea1ng trong d\u1ea5u ngo\u1eb7c: d\u1ea5u ( + ) th\u00e0nh d\u1ea5u ( - ) v\u00e0 d\u1ea5u ( - ) th\u00e0nh d\u1ea5u ( + )<br\/>+ Khi b\u1ecf d\u1ea5u ngo\u1eb7c c\u00f3 d\u1ea5u ( + ) \u0111\u1eb1ng tr\u01b0\u1edbc th\u00ec d\u1ea5u c\u00e1c s\u1ed1 h\u1ea1ng trong ngo\u1eb7c v\u1eabn gi\u1eef nguy\u00ean.<\/span> <br\/><br\/><span class='basic_green'>B\u00e0i gi\u1ea3i:<\/span><br\/>$\\begin{align*}-80 - [-34 - (-15)] &= -80 - (-34 + 15)\\\\&= -80 + 34 - 15 \\end{align*}$<br\/>V\u1eady ta ch\u1ecdn \u0111\u00e1p \u00e1n \u0111\u00fang l\u00e0: <span class='basic_pink'> C. -80 + 34 - 15<\/span><\/span> <br\/>","column":2}]}],"id_ques":1173},{"time":24,"part":[{"title":"L\u1ef1a ch\u1ecdn \u0111\u00e1p \u00e1n \u0111\u00fang nh\u1ea5t","title_trans":"","temp":"multiple_choice","correct":[[1]],"list":[{"point":5,"ques":" B\u1ecf ngo\u1eb7c bi\u1ec3u th\u1ee9c: <br\/>13 - [-6 - (-8) - 23] = <span class='basic_hoi_black'>?<\/span>","select":["A. 13 + 6 - 8 + 23","B. 13 - 6 - 8 + 23","C. 13 + 6 + 8 + 23","D. 13 + 6 - 8 - 23"],"hint":"","explain":" <span class='basic_left'><span class='basic_green'>H\u01b0\u1edbng d\u1eabn:<\/span><br\/> + Khi b\u1ecf d\u1ea5u ngo\u1eb7c c\u00f3 d\u1ea5u (-) \u0111\u1eb1ng tr\u01b0\u1edbc, ta ph\u1ea3i \u0111\u1ed5i t\u1ea5t c\u1ea3 c\u00e1c s\u1ed1 h\u1ea1ng trong d\u1ea5u ngo\u1eb7c: d\u1ea5u ( + ) th\u00e0nh d\u1ea5u ( - ) v\u00e0 d\u1ea5u ( - ) th\u00e0nh d\u1ea5u ( + )<br\/>+ Khi b\u1ecf d\u1ea5u ngo\u1eb7c c\u00f3 d\u1ea5u ( + ) \u0111\u1eb1ng tr\u01b0\u1edbc th\u00ec d\u1ea5u c\u00e1c s\u1ed1 h\u1ea1ng trong ngo\u1eb7c v\u1eabn gi\u1eef nguy\u00ean.<\/span> <br\/><br\/><span class='basic_green'>B\u00e0i gi\u1ea3i:<\/span><br\/>$\\begin{align*}13 - [-6 - (-8) - 23] &= 13 - (-6 + 8 - 23)\\\\&= 13 + 6 - 8 + 23 \\end{align*}$<br\/>V\u1eady ta ch\u1ecdn \u0111\u00e1p \u00e1n \u0111\u00fang l\u00e0: <span class='basic_pink'> A. 13 + 6 - 8 + 23<\/span><\/span> <br\/>","column":2}]}],"id_ques":1174},{"time":24,"part":[{"title":"L\u1ef1a ch\u1ecdn \u0111\u00e1p \u00e1n \u0111\u00fang nh\u1ea5t","title_trans":"","temp":"multiple_choice","correct":[[1]],"list":[{"point":5,"ques":" Gi\u00e1 tr\u1ecb c\u1ee7a bi\u1ec3u th\u1ee9c A = x + y - (-8) t\u1ea1i x = -25; y = 18 l\u00e0:","select":["A. 1","B. -1","C. 51","D. -51"],"hint":"Thay gi\u00e1 tr\u1ecb c\u1ee7a x v\u00e0 y v\u00e0o bi\u1ec3u th\u1ee9c A r\u1ed3i t\u00ednh ","explain":" <span class='basic_left'><span class='basic_green'>H\u01b0\u1edbng d\u1eabn:<\/span><br\/> B\u01b0\u1edbc 1: Thay gi\u00e1 tr\u1ecb c\u1ee7a x v\u00e0 y v\u00e0o bi\u1ec3u th\u1ee9c A<br\/>B\u01b0\u1edbc 2: T\u00ednh gi\u00e1 tr\u1ecb bi\u1ec3u th\u1ee9c<\/span> <br\/><br\/><span class='basic_green'>B\u00e0i gi\u1ea3i:<\/span><br\/> Thay x = -25; y = 18 v\u00e0o bi\u1ec3u th\u1ee9c A ta \u0111\u01b0\u1ee3c:<br\/>$\\begin{align*}A &= (-25) + 18 - (-8)\\\\&= -25 + 18 + 8 \\\\&= 18 + 8 - 25\\\\&= 26 - 25\\\\&= 1\\end{align*}$<br\/>V\u1eady ta ch\u1ecdn \u0111\u00e1p \u00e1n \u0111\u00fang l\u00e0: <span class='basic_pink'> A. 1<\/span><\/span> <br\/>","column":2}]}],"id_ques":1175},{"time":24,"part":[{"title":"L\u1ef1a ch\u1ecdn \u0111\u00e1p \u00e1n \u0111\u00fang nh\u1ea5t","title_trans":"","temp":"multiple_choice","correct":[[3]],"list":[{"point":5,"ques":" Gi\u00e1 tr\u1ecb c\u1ee7a bi\u1ec3u th\u1ee9c A = x - y - (-55) t\u1ea1i x = 38; y = -7 l\u00e0:","select":["A. 10","B. -10","C. 100","D. -100"],"hint":"Thay gi\u00e1 tr\u1ecb c\u1ee7a x v\u00e0 y v\u00e0o bi\u1ec3u th\u1ee9c A r\u1ed3i t\u00ednh ","explain":" <span class='basic_left'><span class='basic_green'>H\u01b0\u1edbng d\u1eabn:<\/span><br\/> B\u01b0\u1edbc 1: Thay gi\u00e1 tr\u1ecb c\u1ee7a x v\u00e0 y v\u00e0o bi\u1ec3u th\u1ee9c A<br\/>B\u01b0\u1edbc 2: T\u00ednh gi\u00e1 tr\u1ecb bi\u1ec3u th\u1ee9c<\/span> <br\/><br\/><span class='basic_green'>B\u00e0i gi\u1ea3i:<\/span><br\/> Thay x = 38; y = -7 v\u00e0o bi\u1ec3u th\u1ee9c A ta \u0111\u01b0\u1ee3c:<br\/>$\\begin{align*}A &= 38 - (-7) - (-55)\\\\&= 38 + 7 + 55 \\\\&= 45 + 55\\\\&= 100\\end{align*}$<br\/>V\u1eady ta ch\u1ecdn \u0111\u00e1p \u00e1n \u0111\u00fang l\u00e0: <span class='basic_pink'> C. 100<\/span><\/span> <br\/>","column":2}]}],"id_ques":1176},{"time":24,"part":[{"title":"\u0110i\u1ec1n s\u1ed1 th\u00edch h\u1ee3p v\u00e0o ch\u1ed7 tr\u1ed1ng","title_trans":"","temp":"fill_the_blank","correct":[[["3","+3"],["88","+88"]]],"list":[{"point":5,"width":60,"type_input":"","ques":"<table><tr><th>a<\/th><th>15<\/th><th>112<\/th><\/tr><tr><td>b<\/td><td>18<\/td><td>200<\/td><\/tr><tr><td>-a + b<\/td><td>_input_<\/td><td>_input_<\/td><\/tr><\/table>","hint":"","explain":"<span class='basic_left'><span class='basic_green'>H\u01b0\u1edbng d\u1eabn:<\/span><br\/><b> -a + b = b - a<\/b><\/span> <br\/><br\/><span class='basic_green'>B\u00e0i gi\u1ea3i:<\/span><br\/>V\u1edbi <b> a = 15; b = 18<\/b> th\u00ec:<br\/>$\\begin{align*}-a + b &= b - a\\\\&= 18 - 15 \\\\&= 3\\end{align*}$<br\/>V\u1edbi <b> a = 112; b = 200<\/b> th\u00ec:<br\/>$\\begin{align*}-a + b &= b - a\\\\&= 200 - 112 \\\\&= 88\\end{align*}$<br\/>V\u1eady c\u00e1c s\u1ed1 c\u1ea7n \u0111i\u1ec1n v\u00e0o \u00f4 tr\u1ed1ng l\u1ea7n l\u01b0\u1ee3t t\u1eeb tr\u00e1i qua ph\u1ea3i l\u00e0: <span class='basic_pink'> 3; 88<\/span><\/span> <br\/> "}]}],"id_ques":1177},{"time":24,"part":[{"title":"\u0110i\u1ec1n s\u1ed1 th\u00edch h\u1ee3p v\u00e0o ch\u1ed7 tr\u1ed1ng","title_trans":"","temp":"fill_the_blank","correct":[[["-7"],["-9"]]],"list":[{"point":5,"width":60,"type_input":"","ques":"<table><tr><th>a<\/th><th>11<\/th><th>31<\/th><\/tr><tr><td>b<\/td><td>18<\/td><td>40<\/td><\/tr><tr><td>-(-a + b)<\/td><td>_input_<\/td><td>_input_<\/td><\/tr><\/table>","hint":"","explain":"<span class='basic_left'><span class='basic_green'>H\u01b0\u1edbng d\u1eabn:<\/span><br\/><b> - (-a + b) = a - b<\/b><\/span> <br\/><br\/><span class='basic_green'>B\u00e0i gi\u1ea3i:<\/span><br\/>V\u1edbi <b> a = 11; b = 18 <\/b>th\u00ec:<br\/>$\\begin{align*}-(-a + b) &= a - b\\\\&= 11 - 18 \\\\&= 11 + (-18)\\\\&= -7\\end{align*}$<br\/>V\u1edbi <b> a = 31; b = 40 <\/b>th\u00ec:<br\/>$\\begin{align*}-(-a + b) &=a - b\\\\&= 31 - 40 \\\\&= 31 + (-40)\\\\&= -9\\end{align*}$<br\/>V\u1eady c\u00e1c s\u1ed1 c\u1ea7n \u0111i\u1ec1n v\u00e0o \u00f4 tr\u1ed1ng l\u1ea7n l\u01b0\u1ee3t t\u1eeb tr\u00e1i qua ph\u1ea3i l\u00e0: <span class='basic_pink'> -7; -9<\/span><\/span> <br\/> "}]}],"id_ques":1178},{"time":24,"part":[{"title":"\u0110i\u1ec1n s\u1ed1 th\u00edch h\u1ee3p v\u00e0o ch\u1ed7 tr\u1ed1ng","title_trans":"","temp":"fill_the_blank","correct":[[["6","+6"],["12","+12"]]],"list":[{"point":5,"width":60,"type_input":"","ques":"<table><tr><th>a<\/th><th>21<\/th><th>30<\/th><\/tr><tr><td>b<\/td><td>15<\/td><td>18<\/td><\/tr><tr><td>-(-a + b)<\/td><td>_input_<\/td><td>_input_<\/td><\/tr><\/table>","hint":"","explain":"<span class='basic_left'><span class='basic_green'>H\u01b0\u1edbng d\u1eabn:<\/span><br\/><b> - (-a + b) = a - b<\/b><\/span> <br\/><br\/><span class='basic_green'>B\u00e0i gi\u1ea3i:<\/span><br\/>V\u1edbi <b> a = 21; b = 15 <\/b>th\u00ec:<br\/>$\\begin{align*}-(-a + b) &= a - b\\\\&= 21 - 15 \\\\&= 6\\end{align*}$<br\/>V\u1edbi <b> a = 30; b = 18 <\/b>th\u00ec:<br\/>$\\begin{align*}-(-a + b) &=a - b\\\\&= 30 - 18\\\\&= 12\\end{align*}$<br\/>V\u1eady c\u00e1c s\u1ed1 c\u1ea7n \u0111i\u1ec1n v\u00e0o \u00f4 tr\u1ed1ng l\u1ea7n l\u01b0\u1ee3t t\u1eeb tr\u00e1i qua ph\u1ea3i l\u00e0: <span class='basic_pink'> 6 ; 12<\/span><\/span> <br\/> "}]}],"id_ques":1179},{"time":24,"part":[{"title":"\u0110i\u1ec1n s\u1ed1 th\u00edch h\u1ee3p v\u00e0o ch\u1ed7 tr\u1ed1ng","title_trans":"","temp":"fill_the_blank","correct":[[["-168"]]],"list":[{"point":5,"width":60,"type_input":"","ques":" T\u00ednh nhanh: <br\/>(125 - 84 + 15) - (84 + 15 + 125) = _input_","hint":"","explain":"<span class='basic_left'><span class='basic_green'>H\u01b0\u1edbng d\u1eabn:<\/span><br\/> B\u1ecf ngo\u1eb7c r\u1ed3i nh\u00f3m c\u1eb7p s\u1ed1 c\u00f3 t\u1ed5ng ho\u1eb7c hi\u1ec7u b\u1eb1ng 0 hay l\u00e0 s\u1ed1 tr\u00f2n ch\u1ee5c, tr\u00f2n tr\u0103m, tr\u00f2n ngh\u00ecn... \u0111\u1ec3 th\u1ef1c hi\u1ec7n t\u00ednh nhanh.<br\/><b>L\u01b0u \u00fd: <\/b><br\/>+ Khi b\u1ecf d\u1ea5u ngo\u1eb7c c\u00f3 d\u1ea5u (-) \u0111\u1eb1ng tr\u01b0\u1edbc, ta ph\u1ea3i \u0111\u1ed5i t\u1ea5t c\u1ea3 c\u00e1c s\u1ed1 h\u1ea1ng trong d\u1ea5u ngo\u1eb7c: d\u1ea5u ( + ) th\u00e0nh d\u1ea5u ( - ) v\u00e0 d\u1ea5u ( - ) th\u00e0nh d\u1ea5u ( + )<br\/>+ Khi b\u1ecf d\u1ea5u ngo\u1eb7c c\u00f3 d\u1ea5u ( + ) \u0111\u1eb1ng tr\u01b0\u1edbc th\u00ec d\u1ea5u c\u00e1c s\u1ed1 h\u1ea1ng trong ngo\u1eb7c v\u1eabn gi\u1eef nguy\u00ean.<\/span> <br\/><br\/><span class='basic_left'><span class='basic_green'>B\u00e0i gi\u1ea3i:<\/span><br\/>$\\begin{align*}(125 - 84 + 15) - (84 + 15 + 125) &= 125 - 84 + 15 - 84 - 15 - 125 \\\\&= (125 - 125) + (15 - 15) - (84 + 84)\\\\&= 0 + 0 - 168\\\\&= -168\\end{align*}$<br\/>V\u1eady s\u1ed1 c\u1ea7n \u0111i\u1ec1n v\u00e0o \u00f4 tr\u1ed1ng l\u00e0: <span class='basic_pink'> -168<\/span><\/span> <br\/> <span class='basic_left'><span class='basic_green'>Nh\u1eadn x\u00e9t:<\/span> <br\/>Trong m\u1ed9t t\u1ed5ng \u0111\u1ea1i s\u1ed1, ta c\u00f3 th\u1ec3: \u0111\u1eb7t d\u1ea5u ngo\u1eb7c \u0111\u1ec3 nh\u00f3m c\u00e1c s\u1ed1 h\u1ea1ng m\u1ed9t c\u00e1ch t\u00f9y \u00fd v\u1edbi ch\u00fa \u00fd r\u1eb1ng n\u1ebfu tr\u01b0\u1edbc d\u1ea5u ngo\u1eb7c l\u00e0 d\u1ea5u ( - ) th\u00ec ph\u1ea3i \u0111\u1ed1i d\u1ea5u t\u1ea5t c\u1ea3 c\u00e1c s\u1ed1 h\u1ea1ng trong ngo\u1eb7c<br\/><b>V\u00ed d\u1ee5: a - b - c = a - (b + c)<\/b><\/span><\/span> "}]}],"id_ques":1180}],"lesson":{"save":0,"level":2}}