{"segment":[{"time":24,"part":[{"title":"\u0110i\u1ec1n \u0111\u00e1p \u00e1n \u0111\u00fang v\u00e0o \u00f4 tr\u1ed1ng","title_trans":"","temp":"fill_the_blank","correct":[[["2"]]],"list":[{"point":10,"width":50,"type_input":"","input_hint":["frac"],"ques":"T\u00ednh gi\u00e1 tr\u1ecb c\u1ee7a bi\u1ec3u th\u1ee9c. <br\/> $\\left( 17 \\dfrac{3535}{88375} - 16\\dfrac{1001}{1365} \\right) . 3\\dfrac{6}{23} + 3\\dfrac{6}{23} : \\left( 5 - 1\\dfrac{187}{253} \\right) $ = _input_ ","hint":"R\u00fat g\u1ecdn ph\u00e2n s\u1ed1 r\u1ed3i th\u1ef1c hi\u1ec7n ph\u00e9p t\u00ednh","explain":" <span class='basic_left'><span class='basic_green'>H\u01b0\u1edbng d\u1eabn:<\/span><br\/> <b> B\u01b0\u1edbc 1: <\/b> R\u00fat g\u1ecdn c\u00e1c ph\u00e2n s\u1ed1 \u0111\u1ebfn t\u1ed1i gi\u1ea3n <br\/> <b> B\u01b0\u1edbc 2: <\/b> Th\u1ef1c hi\u1ec7n c\u00e1c ph\u00e9p t\u00ednh l\u1ea7n l\u01b0\u1ee3t theo th\u1ee9 t\u1ef1 th\u1ef1c hi\u1ec7n c\u00e1c ph\u00e9p t\u00ednh <\/span> <br\/><br\/> <span class='basic_green'>B\u00e0i gi\u1ea3i:<\/span><br\/> $ \\begin{align*} & \\left( 17 \\dfrac{3535}{88375} - 16\\dfrac{1001}{1365} \\right) . 3\\dfrac{6}{23} + 3\\dfrac{6}{23} : \\left( 5 - 1\\dfrac{187}{253} \\right) \\\\ & = \\left( 17\\dfrac{1}{25} - 16\\dfrac{11}{15} \\right) . 3\\dfrac{6}{23} + 3\\dfrac{6}{23} : \\left(5 - 1\\dfrac{17}{23} \\right) \\\\ &= \\left( 17\\dfrac{3}{75} - 16\\dfrac{55}{75} \\right) . 3\\dfrac{6}{23} + 3\\dfrac{6}{23} : \\left( 4\\dfrac{23}{23} - 1\\dfrac{17}{23} \\right) \\\\ &= \\left( 16\\dfrac{78}{75} - 16\\dfrac{55}{75} \\right) . 3\\dfrac{6}{23} + 3\\dfrac{6}{23} : 3\\dfrac{6}{23} \\\\ &= \\dfrac{23}{75} . \\dfrac{75}{23} + 1 \\\\ &= 1 + 1 = 2 \\end{align*} $<br\/> <span class='basic_green'> <i> Nh\u1eadn x\u00e9t: C\u1ea7n r\u00fat g\u1ecdn c\u00e1c ph\u00e2n s\u1ed1 \u0111\u1ebfn t\u1ed1i gi\u1ea3n r\u1ed3i m\u1edbi th\u1ef1c hi\u1ec7n ph\u00e9p t\u00ednh <br\/> \u1ede b\u00e0i n\u00e0y h\u1ecdc sinh hay m\u1eafc sai l\u1ea7m l\u00e0 nh\u00f3m $3\\dfrac{6}{23}$ l\u00e0m nh\u00e2n t\u1eed chung nh\u01b0ng vi\u1ec7c l\u00e0m n\u00e0y l\u00e0 kh\u00f4ng \u0111\u00fang v\u00ec \u1edf s\u1ed1 h\u1ea1ng th\u1ee9 nh\u1ea5t ta c\u00f3 $\\left( 17 \\dfrac{3535}{88375} - 16\\dfrac{1001}{1365} \\right) . 3\\dfrac{6}{23}$, c\u00f2n \u1edf s\u1ed1 h\u1ea1ng th\u1ee9 2 c\u00f3 $3\\dfrac{6}{23} : \\left( 5 - 1\\dfrac{187}{253} \\right)$ t\u1ee9c l\u00e0 vai tr\u00f2 c\u1ee7a $3\\dfrac{6}{23}$ kh\u00f4ng gi\u1ed1ng nhau n\u00ean ta kh\u00f4ng \u0111\u1eb7t ra ngo\u00e0i l\u00e0m nh\u00e2n t\u1eed chung \u0111\u01b0\u1ee3c <\/i> <\/span> "}]}],"id_ques":1741},{"time":24,"part":[{"title":"\u0110i\u1ec1n \u0111\u00e1p \u00e1n \u0111\u00fang v\u00e0o \u00f4 tr\u1ed1ng","title_trans":"","temp":"fill_the_blank","correct":[[["2"],["1"],["3"]]],"list":[{"point":10,"width":50,"type_input":"","input_hint":["frac"],"ques":"T\u00ednh gi\u00e1 tr\u1ecb c\u1ee7a bi\u1ec3u th\u1ee9c. <br\/> $\\dfrac{1,6 : \\left( 1\\dfrac{3}{5} . 1,25\\right) }{0,64 - \\dfrac{1}{25}} + \\dfrac{ \\left( 1,08 - \\dfrac{2}{25} \\right) : \\dfrac{4}{7}}{\\left( 5\\dfrac{5}{9} - 2\\dfrac{1}{4} \\right) . 2\\dfrac{2}{17}} + (0,6 . 0,5) : \\dfrac{2}{5} $ = _input_<div class=\"frac123\"><div class=\"ts\">_input_<\/div><div class=\"ms\">_input_<\/div><\/div>","hint":"Vi\u1ebft $1\\dfrac{3}{5} = 1,6$; $\\dfrac{2}{25} = 0,08$; $\\dfrac{1}{25} = 0,04$; $\\dfrac{2}{5} = 0,4$ ","explain":" <span class='basic_green'>B\u00e0i gi\u1ea3i:<\/span><br\/> $ \\begin{align*} &\\dfrac{1,6 : \\left( 1\\dfrac{3}{5} . 1,25\\right) }{0,64 - \\dfrac{1}{25}} + \\dfrac{ \\left( 1,08 - \\dfrac{2}{25} \\right) : \\dfrac{4}{7}}{\\left( 5\\dfrac{5}{9} - 2\\dfrac{1}{4} \\right) . 2\\dfrac{2}{17}} + (0,6 . 0,5) : \\dfrac{2}{5} \\\\ &= \\dfrac{1,6 : \\left( \\dfrac{8}{5} . 1,25 \\right)}{0,64 - 0,04} + \\dfrac{ \\left(1,08 - 0,08 \\right) : \\dfrac{4}{7}}{ \\left( \\dfrac{50}{9} - \\dfrac{9}{4} \\right) . \\dfrac{36}{17}} + (0,6 . 0,5) : 0,4 \\\\ &= \\dfrac{1,6 : (1,6 . 1,25)}{0,6} + \\dfrac{ 1 : \\dfrac{4}{7}}{\\left( \\dfrac{200}{36} - \\dfrac{81}{36} \\right) . \\dfrac{36}{17}} + 0,3 : 0,4 \\\\ &= \\dfrac{1,6 : 2}{0,6} + \\dfrac{\\dfrac{7}{4}}{\\dfrac{119}{36} . \\dfrac{36}{17}} + \\dfrac{0,3}{0,4} \\\\ &= \\dfrac{0,8}{0,6} + \\dfrac{7}{4} . \\dfrac{17}{119} + \\dfrac{3}{4} \\\\ &= \\dfrac{4}{3} + \\dfrac{1}{4} + \\dfrac{3}{4} \\\\ &= \\dfrac{4}{3} + 1 \\\\ &= 2\\dfrac{1}{3} \\end{align*} $<br\/> <span class='basic_green'> <i> Nh\u1eadn x\u00e9t: V\u1edbi nh\u1eefng b\u00e0i t\u00ednh gi\u00e1 tr\u1ecb bi\u1ec3u th\u1ee9c, ch\u00fang ta c\u1ea7n quan s\u00e1t k\u0129 tr\u01b0\u1edbc khi bi\u1ebfn \u0111\u1ed5i: C\u00f3 nh\u1eefng b\u00e0i ch\u00fang ta chuy\u1ec3n t\u1ea5t c\u1ea3 c\u00e1c s\u1ed1 ra ph\u00e2n s\u1ed1, s\u1ed1 th\u1eadp ph\u00e2n ho\u1eb7c h\u1ed7n s\u1ed1 \u0111\u1ec3 t\u00ednh. C\u00f3 nh\u1eefng b\u00e0i ch\u00fang ta nh\u00f3m c\u00e1c ph\u00e2n s\u1ed1 v\u1edbi nhau, c\u00e1c h\u1ed7n s\u1ed1 v\u1edbi nhau, c\u00e1c s\u1ed1 th\u1eadp ph\u00e2n v\u1edbi nhau \u0111\u1ec3 t\u00ednh, vi\u1ec7c n\u00e0y gi\u00fap cho vi\u1ec7c th\u1ef1c hi\u1ec7n c\u00e1c ph\u00e9p t\u00ednh tr\u1edf n\u00ean \u0111\u01a1n gi\u1ea3n h\u01a1n <\/i> <\/span> "}]}],"id_ques":1742},{"time":24,"part":[{"title":"\u0110i\u1ec1n \u0111\u00e1p \u00e1n \u0111\u00fang v\u00e0o \u00f4 tr\u1ed1ng","title_trans":"","temp":"fill_the_blank","correct":[[["247"],["44"]]],"list":[{"point":10,"width":50,"type_input":"","input_hint":["frac"],"ques":"T\u00ecm x bi\u1ebft: <br\/><br\/> $0,875 . \\left( \\dfrac{6}{5}x - \\dfrac{13}{2} \\right) = \\dfrac{1}{2}x - 2,6$ <br\/> \u0110\u00e1p \u00e1n l\u00e0: $x$ = <div class=\"frac123\"><div class=\"ts\">_input_<\/div><div class=\"ms\">_input_<\/div><\/div>","hint":"Vi\u1ebft c\u00e1c s\u1ed1 th\u1eadp ph\u00e2n d\u01b0\u1edbi d\u1ea1ng ph\u00e2n s\u1ed1 r\u1ed3i bi\u1ebfn \u0111\u1ed5i v\u00e0 t\u00ecm x ","explain":" <span class='basic_left'><span class='basic_green'>H\u01b0\u1edbng d\u1eabn:<\/span><br\/> <b> B\u01b0\u1edbc 1: <\/b> Vi\u1ebft c\u00e1c s\u1ed1 th\u1eadp ph\u00e2n d\u01b0\u1edbi d\u1ea1ng ph\u00e2n s\u1ed1 <br\/> <b> B\u01b0\u1edbc 2: <\/b> Nh\u00e2n ph\u00e1 ngo\u1eb7c \u1edf v\u1ebf tr\u00e1i <br\/> <b> B\u01b0\u1edbc 3: <\/b> Chuy\u1ec3n $\\dfrac{1}{2}x$ sang v\u1ebf tr\u00e1i v\u00e0 c\u00e1c s\u1ed1 h\u1ea1ng kh\u00f4ng ch\u1ee9a x sang v\u1ebf ph\u1ea3i <br\/> <b> B\u01b0\u1edbc 4: <\/b> Bi\u1ebfn \u0111\u1ed5i v\u00e0 t\u00ecm x <\/span> <br\/><br\/> <span class='basic_green'>B\u00e0i gi\u1ea3i:<\/span><br\/> $ \\begin{align*} 0,875 . \\left( \\dfrac{6}{5}x - \\dfrac{13}{2} \\right) &= \\dfrac{1}{2}x - 2,6 \\\\ \\dfrac{875}{1000} . \\left( \\dfrac{6}{5}x - \\dfrac{13}{2} \\right) &= \\dfrac{1}{2}x - \\dfrac{26}{10} \\\\ \\dfrac{7}{8} . \\left( \\dfrac{6}{5}x - \\dfrac{13}{2} \\right) &= \\dfrac{1}{2}x - \\dfrac{13}{5} \\\\ \\dfrac{21}{20}x - \\dfrac{91}{16} &= \\dfrac{1}{2}x - \\dfrac{13}{5} \\\\ \\dfrac{21}{20}x - \\dfrac{1}{2}x &= \\dfrac{91}{16} - \\dfrac{13}{5} \\\\ \\dfrac{11}{20}x &= \\dfrac{247}{80} \\\\ x &= \\dfrac{247}{44} \\end{align*} $ "}]}],"id_ques":1743},{"time":24,"part":[{"title":"\u0110i\u1ec1n \u0111\u00e1p \u00e1n \u0111\u00fang v\u00e0o \u00f4 tr\u1ed1ng","title_trans":"","temp":"fill_the_blank","correct":[[["135"],["176"]]],"list":[{"point":10,"width":50,"type_input":"","input_hint":["frac"],"ques":"T\u00ecm x bi\u1ebft: <br\/><br\/> $0,8 - \\dfrac{2}{5} . \\left( x - \\dfrac{1}{2} \\right) = 1 - \\left( 3\\dfrac{1}{3}x - 2,25 \\right) $ <br\/> \u0110\u00e1p \u00e1n l\u00e0: $x$ = <div class=\"frac123\"><div class=\"ts\">_input_<\/div><div class=\"ms\">_input_<\/div><\/div>","hint":"","explain":" <span class='basic_left'><span class='basic_green'>H\u01b0\u1edbng d\u1eabn:<\/span><br\/> <b> B\u01b0\u1edbc 1: <\/b> Vi\u1ebft c\u00e1c s\u1ed1 th\u1eadp ph\u00e2n d\u01b0\u1edbi d\u1ea1ng ph\u00e2n s\u1ed1 <br\/> <b> B\u01b0\u1edbc 2: <\/b> Nh\u00e2n ph\u00e1 ngo\u1eb7c \u1edf v\u1ebf tr\u00e1i v\u00e0 ph\u00e1 ngo\u1eb7c v\u1ebf ph\u1ea3i <br\/> <b> B\u01b0\u1edbc 3: <\/b> Chuy\u1ec3n c\u00e1c s\u1ed1 h\u1ea1ng ch\u1ee9a x sang v\u1ebf tr\u00e1i v\u00e0 s\u1ed1 h\u1ea1ng kh\u00f4ng ch\u1ee9a x sang v\u1ebf ph\u1ea3i <br\/> <b> B\u01b0\u1edbc 4: <\/b> Bi\u1ebfn \u0111\u1ed5i v\u00e0 t\u00ecm x <\/span> <br\/><br\/> <span class='basic_green'>B\u00e0i gi\u1ea3i:<\/span><br\/> $ \\begin{align*} 0,8 - \\dfrac{2}{5} . \\left( x - \\dfrac{1}{2} \\right) &= 1 - \\left( 3\\dfrac{1}{3}x - 2,25 \\right) \\\\ \\dfrac{8}{10} - \\dfrac{2}{5} . \\left( x - \\dfrac{1}{2} \\right) &= 1 - \\left( \\dfrac{10}{3}x - \\dfrac{225}{100} \\right) \\\\ \\dfrac{4}{5} - \\dfrac{2}{5}x + \\dfrac{1}{5} &= 1 - \\dfrac{10}{3}x + \\dfrac{9}{4} \\\\ 1 - \\dfrac{2}{5}x &= \\dfrac{13}{4} - \\dfrac{10}{3}x \\\\ \\dfrac{10}{3}x - \\dfrac{2}{5}x &= \\dfrac{13}{4} - 1 \\\\ \\dfrac{50}{15}x - \\dfrac{6}{15}x &= \\dfrac{13}{4} - \\dfrac{4}{4} \\\\ \\dfrac{44}{15}x &= \\dfrac{9}{4} \\\\ x &= \\dfrac{9}{4} : \\dfrac{44}{15} \\\\ x &= \\dfrac{135}{176} \\end{align*} $"}]}],"id_ques":1744},{"time":24,"part":[{"title":"\u0110i\u1ec1n \u0111\u00e1p \u00e1n \u0111\u00fang v\u00e0o \u00f4 tr\u1ed1ng","title_trans":"","temp":"fill_the_blank","correct":[[["32"],["24"]]],"list":[{"point":10,"width":50,"type_input":"","ques":"T\u00ednh s\u1ed1 tu\u1ed5i c\u1ee7a anh v\u00e0 em, bi\u1ebft r\u1eb1ng 62,5% tu\u1ed5i anh th\u00ec l\u1edbn h\u01a1n 75% tu\u1ed5i em l\u00e0 2 n\u0103m, v\u00e0 50% tu\u1ed5i anh th\u00ec l\u1edbn h\u01a1n 37,5% tu\u1ed5i em l\u00e0 7 n\u0103m. <br\/> \u0110\u00e1p s\u1ed1: Tu\u1ed5i anh: _input_ tu\u1ed5i <br\/> Tu\u1ed5i em: _input_ tu\u1ed5i ","hint":"50% tu\u1ed5i anh th\u00ec l\u1edbn h\u01a1n 37,5% tu\u1ed5i em l\u00e0 7 n\u0103m. V\u1eady 100% tu\u1ed5i anh th\u00ec l\u1edbn h\u01a1n 75% tu\u1ed5i em l\u00e0 14 n\u0103m","explain":"<span class='basic_left'><span class='basic_green'>H\u01b0\u1edbng d\u1eabn:<\/span><br\/> <b> B\u01b0\u1edbc 1: <\/b> T\u00ecm 100% tu\u1ed5i anh h\u01a1n 75% tu\u1ed5i em l\u00e0 bao nhi\u00eau tu\u1ed5i <br\/> <b> B\u01b0\u1edbc 2: <\/b> T\u00ednh (100% - 62,5%) tu\u1ed5i anh l\u00e0 bao nhi\u00eau tu\u1ed5i <br\/> <b> B\u01b0\u1edbc 3: <\/b> T\u00ednh tu\u1ed5i c\u1ee7a anh <br\/> <b> B\u01b0\u1edbc 4: <\/b> T\u00ednh 75% tu\u1ed5i em <br\/> L\u1ea5y tu\u1ed5i anh - 14 tu\u1ed5i <br\/> <b> B\u01b0\u1edbc 5: <\/b> T\u00ednh tu\u1ed5i c\u1ee7a em <\/span> <br\/><br\/> <span class='basic_green'>B\u00e0i gi\u1ea3i:<\/span><br\/> <b> Nh\u1eadn x\u00e9t: <\/b> Theo \u0111\u1ec1 b\u00e0i 50% tu\u1ed5i anh l\u1edbn h\u01a1n 37,5% tu\u1ed5i em l\u00e0 7 n\u0103m. <br\/> V\u1eady 100% tu\u1ed5i anh l\u1edbn h\u01a1n 75% tu\u1ed5i em l\u00e0 14 n\u0103m <br\/> M\u00e0 62,5% tu\u1ed5i anh l\u1edbn h\u01a1n 75% tu\u1ed5i em l\u00e0 2 n\u0103m <br\/> N\u00ean 100% - 62,5% = 37,5% tu\u1ed5i anh l\u00e0 14 - 2 = 12 n\u0103m <br\/> V\u1eady tu\u1ed5i anh l\u00e0: <br\/> 12 : 37,5% = 12 : $\\dfrac{37,5}{100}$ = 32 (tu\u1ed5i) <br\/> 75% tu\u1ed5i em b\u1eb1ng: <br\/> 32 - 14 = 18 (tu\u1ed5i) <br\/> Tu\u1ed5i em l\u00e0: <br\/> 18 : 75% = 18 : $\\dfrac{75}{100}$ = 24 (tu\u1ed5i) <br\/> \u0110\u00e1p s\u1ed1: Tu\u1ed5i anh: 32 tu\u1ed5i <br\/> Tu\u1ed5i em: 24 tu\u1ed5i <br\/> <span class='basic_pink'> V\u1eady c\u00e1c s\u1ed1 c\u1ea7n \u0111i\u1ec1n l\u00e0: 32; 24 <\/span> "}]}],"id_ques":1745},{"time":24,"part":[{"title":"L\u1ef1a ch\u1ecdn \u0111\u00e1p \u00e1n \u0111\u00fang nh\u1ea5t","title_trans":"","temp":"multiple_choice","correct":[[4]],"list":[{"point":10,"ques":"T\u00ecm s\u1ed1 nguy\u00ean x th\u1ecfa m\u00e3n. <br\/><br\/> $\\dfrac{-150 . (1352 - 41)}{(1352 - 41)(150 - 15)} < x < \\dfrac{(2400 : 48) - 250}{350 - (3600 : 12)}$","select":["A. x = -1 ","B. x = -2 ","C. x = -3","D. Kh\u00f4ng c\u00f3 gi\u00e1 tr\u1ecb nguy\u00ean n\u00e0o c\u1ee7a x th\u1ecfa m\u00e3n "],"hint":"","explain":"<span class='basic_left'><span class='basic_green'>H\u01b0\u1edbng d\u1eabn:<\/span><br\/> <b> B\u01b0\u1edbc 1: <\/b> T\u00ednh $\\dfrac{-150 . (1352 - 41)}{(1352 - 41)(150 - 15)}$ (1) <br\/> <b> B\u01b0\u1edbc 2: <\/b> T\u00ednh $\\dfrac{(2400 : 48) - 250}{350 - (3600 : 12)}$ (2) <br\/> <b> B\u01b0\u1edbc 3: <\/b> T\u00ecm c\u00e1c gi\u00e1 tr\u1ecb nguy\u00ean c\u1ee7a x th\u1ecfa m\u00e3n (1) < x < (2) <\/span> <br\/><br\/><span class='basic_green'>B\u00e0i gi\u1ea3i:<\/span> <br\/> Ta c\u00f3: <br\/> $ \\dfrac{-150 . (1352 - 41)}{(1352 - 41)(150 - 15)} = \\dfrac{-150}{150 - 15} = \\dfrac{-150}{135} = -1\\dfrac{1}{9}$ <br\/> <br\/> $\\dfrac{(2400 : 48) - 250}{350 - (3600 : 12)} = \\dfrac{50 - 250}{350 - 300} = \\dfrac{-200}{-50} = -4 $ <br\/> $\\Rightarrow$ $-1 \\dfrac{1}{9} < x < -4 $ <br\/> V\u00ec $-1\\dfrac{1}{9} > -4$ $\\Rightarrow$ Kh\u00f4ng c\u00f3 gi\u00e1 tr\u1ecb nguy\u00ean n\u00e0o c\u1ee7a x th\u1ecfa m\u00e3n <br\/> <span class='basic_pink'> V\u1eady \u0111\u00e1p \u00e1n \u0111\u00fang l\u00e0: D <\/span> ","column":2}]}],"id_ques":1746},{"time":24,"part":[{"title":"L\u1ef1a ch\u1ecdn \u0111\u00e1p \u00e1n \u0111\u00fang nh\u1ea5t","title_trans":"","temp":"multiple_choice","correct":[[2]],"list":[{"point":10,"ques":"Cho A = $\\dfrac{n}{n + 1}$; B = $\\dfrac{n + 2}{n + 3}$ $(n \\in \\mathbb{N})$ <br\/> Kh\u1eb3ng \u0111\u1ecbnh n\u00e0o sau \u0111\u00e2y \u0111\u00fang? ","select":["A. A > B ","B. A < B ","C. A = B"],"hint":"S\u1eed d\u1ee5ng ph\u01b0\u01a1ng ph\u00e1p so s\u00e1nh ph\u1ea7n b\u00f9","explain":" <span class='basic_left'><span class='basic_green'>H\u01b0\u1edbng d\u1eabn:<\/span><br\/> Nh\u1eadn x\u00e9t: Nh\u1eadn th\u1ea5y n + 1 - n = 1; n + 3 - (n + 2) = 1 n\u00ean ta s\u1eed d\u1ee5ng ph\u01b0\u01a1ng ph\u00e1p so s\u00e1nh ph\u1ea7n b\u00f9 <\/span> <br\/><br\/> <span class='basic_green'>B\u00e0i gi\u1ea3i:<\/span> <br\/> Ta c\u00f3: <br\/> $A = \\dfrac{n}{n + 1} = \\dfrac{n + 1 - 1}{n + 1} = \\dfrac{n + 1}{n + 1} - \\dfrac{1}{n + 1} = 1 - \\dfrac{1}{n + 1}$ <br\/><br\/> $\\dfrac{n + 2}{n + 3} = \\dfrac{n + 3 - 1}{n + 3} = \\dfrac{n + 3}{n + 3} - \\dfrac{1}{n + 3} = 1 - \\dfrac{1}{n + 3}$ <br\/> V\u00ec $\\dfrac{1}{n + 1} > \\dfrac{1}{n + 3}$ <br\/> N\u00ean $1 - \\dfrac{1}{n + 1} < 1 - \\dfrac{1}{n + 3}$ <br\/> $\\Rightarrow$ A < B <br\/> <span class='basic_pink'> V\u1eady \u0111\u00e1p \u00e1n \u0111\u00fang l\u00e0: B <\/span> <br\/> <span class='basic_left'><span class='basic_green'><i> Nh\u1eadn x\u00e9t: V\u1edbi nh\u1eefng b\u00e0i so s\u00e1nh ph\u00e2n s\u1ed1 m\u00e0 t\u1eed s\u1ed1 c\u1ee7a m\u1ed7i ph\u00e2n s\u1ed1 \u0111\u1ec1u l\u1edbn h\u01a1n m\u1eabu a \u0111\u01a1n v\u1ecb th\u00ec ta s\u1eed d\u1ee5ng ph\u01b0\u01a1ng ph\u00e1p so s\u00e1nh ph\u1ea7n h\u01a1n <br\/> N\u1ebfu t\u1eed s\u1ed1 m\u1ed7i ph\u00e2n s\u1ed1 \u0111\u1ec1u nh\u1ecf h\u01a1n m\u1eabu s\u1ed1 a \u0111\u01a1n v\u1ecb th\u00ec ta s\u1eed d\u1ee5ng ph\u01b0\u01a1ng ph\u00e1p so s\u00e1nh ph\u1ea7n b\u00f9 <\/i> <\/span>","column":3}]}],"id_ques":1747},{"time":24,"part":[{"title":"L\u1ef1a ch\u1ecdn \u0111\u00e1p \u00e1n \u0111\u00fang nh\u1ea5t","title_trans":"","temp":"multiple_choice","correct":[[1]],"list":[{"point":10,"ques":"Cho A = $\\dfrac{10^{15} + 1}{10^{16} + 1}$; B = $\\dfrac{10^{16} + 1}{10^{17} + 1}$ <br\/> Kh\u1eb3ng \u0111\u1ecbnh n\u00e0o sau \u0111\u00e2y \u0111\u00fang? ","select":["A. A > B ","B. A < B ","C. A = B"],"hint":"T\u00ednh 10A v\u00e0 10B r\u1ed3i s\u1eed d\u1ee5ng ph\u01b0\u01a1ng ph\u00e1p so s\u00e1nh ph\u1ea7n h\u01a1n","explain":" <span class='basic_left'><span class='basic_green'>H\u01b0\u1edbng d\u1eabn:<\/span><br\/> Nh\u1eadn x\u00e9t: Nh\u1eadn th\u1ea5y n\u1ebfu nh\u00e2n m\u1ed7i ph\u00e2n s\u1ed1 tr\u00ean v\u1edbi 10 th\u00ec t\u1eed s\u1ed1 l\u1edbn h\u01a1n m\u1eabu s\u1ed1 9 \u0111\u01a1n v\u1ecb khi \u0111\u00f3 <br\/> <b> B\u01b0\u1edbc 1: <\/b> S\u1eed d\u1ee5ng ph\u01b0\u01a1ng ph\u00e1p so s\u00e1nh ph\u1ea7n h\u01a1n so s\u00e1nh 10A v\u1edbi 10B <br\/> <b> <\/span> <br\/><br\/> <span class='basic_green'>B\u00e0i gi\u1ea3i:<\/span> <br\/> Ta c\u00f3: <br\/> $10A = 10 . \\dfrac{10^{15} + 1}{10^{16} + 1} = \\dfrac{10^{16} + 10}{10^{16} + 1} = 1 + \\dfrac{9}{10^{16} + 1}$ <br\/> <br\/> $10B = 10 . \\dfrac{10^{16} + 1}{10^{17} + 1} = \\dfrac{10^{17} + 10}{10^{17} + 1} = 1 + \\dfrac{9}{10^{17} + 1}$ <br\/> <br\/> V\u00ec $\\dfrac{9}{10^{16} + 1} > \\dfrac{9}{10^{17} + 1}$ n\u00ean $1 + \\dfrac{9}{10^{16} + 1}$ > $ 1 + \\dfrac{9}{10^{17} + 1}$ <br\/> $\\Rightarrow$ 10A > 10B, do \u0111\u00f3 A > B <br\/> <span class='basic_pink'> V\u1eady \u0111\u00e1p \u00e1n \u0111\u00fang l\u00e0: A <\/span>","column":3}]}],"id_ques":1748},{"time":24,"part":[{"title":"\u0110i\u1ec1n \u0111\u00e1p \u00e1n \u0111\u00fang v\u00e0o \u00f4 tr\u1ed1ng","title_trans":"","temp":"fill_the_blank","correct":[[["8"],["16"]]],"list":[{"point":10,"width":50,"type_input":"","ques":"Hai xe \u00f4 t\u00f4 \u0111i t\u1eeb hai \u0111\u1ecba \u0111i\u1ec3m A v\u00e0 B v\u1ec1 ph\u00eda nhau, xe th\u1ee9 nh\u1ea5t kh\u1edfi h\u00e0nh t\u1eeb A l\u00fac 7 gi\u1edd, xe th\u1ee9 hai kh\u1edfi h\u00e0nh l\u00fac 7 gi\u1edd 10 ph\u00fat . Bi\u1ebft r\u1eb1ng \u0111\u1ec3 \u0111i qu\u00e3ng \u0111\u01b0\u1eddng AB, xe th\u1ee9 nh\u1ea5t c\u1ea7n 2 gi\u1edd, xe th\u1ee9 hai c\u1ea7n 3 gi\u1edd. H\u1ecfi hai xe g\u1eb7p nhau l\u00fac m\u1ea5y gi\u1edd? <br\/> \u0110\u00e1p s\u1ed1: _input_ gi\u1edd _input_ ph\u00fat ","hint":"Ch\u1ecdn qu\u00e3ng \u0111\u01b0\u1eddng AB l\u00e0m \u0111\u01a1n v\u1ecb quy \u01b0\u1edbc","explain":"<span class='basic_left'><span class='basic_green'>H\u01b0\u1edbng d\u1eabn:<\/span><br\/> <b> B\u01b0\u1edbc 1: <\/b> T\u00ednh trong 1 gi\u1edd xe th\u1ee9 nh\u1ea5t \u0111i \u0111\u01b0\u1ee3c bao nhi\u00eau ph\u1ea7n qu\u00e3ng \u0111\u01b0\u1eddng AB <br\/> Xe th\u1ee9 2 \u0111i \u0111\u01b0\u1ee3c bao nhi\u00eau ph\u1ea7n qu\u00e3ng \u0111\u01b0\u1eddng AB <br\/> L\u1ea5y 1 chia th\u1eddi gian xe \u0111\u00f3 \u0111i h\u1ebft qu\u00e3ng \u0111\u01b0\u1eddng AB <br\/> <b> B\u01b0\u1edbc 2: <\/b> T\u00ednh trong 1 gi\u1edd hai xe g\u1ea7n nhau \u0111\u01b0\u1ee3c bao nhi\u00eau ph\u1ea7n qu\u00e3ng \u0111\u01b0\u1eddng AB <br\/> <b> B\u01b0\u1edbc 3: <\/b> Khi xe th\u1ee9 hai b\u1eaft \u0111\u1ea7u \u0111i th\u00ec xe th\u1ee9 nh\u1ea5t \u0111i \u0111\u01b0\u1ee3c bao nhi\u00eau ph\u1ea7n qu\u00e3ng \u0111\u01b0\u1eddng AB <br\/> (Th\u1eddi gian: 7 gi\u1edd 10 ph\u00fat - 7gi\u1edd = 10 ph\u00fat) <br\/> <b> B\u01b0\u1edbc 4: <\/b> T\u00ednh qu\u00e3ng \u0111\u01b0\u1eddng hai xe c\u00e1ch nhau khi xe th\u1ee9 2 kh\u1edfi h\u00e0nh <br\/> L\u1ea5y qu\u00e3ng \u0111\u01b0\u1eddng AB - qu\u00e3ng \u0111\u01b0\u1eddng xe 1 \u0111i trong 10 ph\u00fat <br\/> <b> B\u01b0\u1edbc 5: <\/b> T\u00ednh th\u1eddi gian t\u1eeb l\u00fac hai xe b\u1eaft \u0111\u1ea7u \u0111i \u0111\u1ebfn khi g\u1eb7p nhau <br\/> <b> B\u01b0\u1edbc 6: <\/b> T\u00ednh hai xe g\u1eb7p nhau l\u00fac <\/span> <br\/><br\/> <span class='basic_green'>B\u00e0i gi\u1ea3i:<\/span><br\/> Ch\u1ecdn qu\u00e3ng \u0111\u01b0\u1eddng AB l\u00e0m \u0111\u01a1n v\u1ecb quy \u01b0\u1edbc <br\/> Trong 1 gi\u1edd xe th\u1ee9 nh\u1ea5t \u0111i \u0111\u01b0\u1ee3c: <br\/> 1 : 2 = $\\dfrac{1}{2}$ (qu\u00e3ng \u0111\u01b0\u1eddng AB) <br\/> Trong 1 gi\u1edd xe 2 \u0111i \u0111\u01b0\u1ee3c: <br\/> $1 : 3 = \\dfrac{1}{3}$ (qu\u00e3ng \u0111\u01b0\u1eddng AB) <br\/> Trong 1 gi\u1edd hai xe g\u1ea7n nhau \u0111\u01b0\u1ee3c: <br\/> $\\dfrac{1}{2} + \\dfrac{1}{3} = \\dfrac{5}{6}$ (qu\u00e3ng \u0111\u01b0\u1eddng AB) <br\/> Trong th\u1eddi gian 7 gi\u1edd 10 ph\u00fat - 7 gi\u1edd = 10 ph\u00fat = $\\dfrac{1}{6}$ gi\u1edd xe th\u1ee9 nh\u1ea5t \u0111i \u0111\u01b0\u1ee3c: <br\/> $\\dfrac{1}{2} . \\dfrac{1}{6} = \\dfrac{1}{12}$ (qu\u00e3ng \u0111\u01b0\u1eddng AB) <br\/> L\u00fac hai xe kh\u1edfi h\u00e0nh hai xe c\u00e1ch nhau: <br\/> $1 - \\dfrac{1}{12} = \\dfrac{11}{12}$ (qu\u00e3ng \u0111\u01b0\u1eddng AB) <br\/> Hai xe g\u1eb7p nhau sau: <br\/> $\\dfrac{11}{12} : \\dfrac{5}{6} = \\dfrac{11}{10}$ (gi\u1edd) = 1 gi\u1edd 6 ph\u00fat <br\/> Hai xe g\u1eb7p nhau l\u00fac: <br\/> 7 gi\u1edd 10 ph\u00fat + 1 gi\u1edd 6 ph\u00fat = 8 gi\u1edd 16 ph\u00fat <br\/> \u0110\u00e1p s\u1ed1: 8 gi\u1edd 16 ph\u00fat <br\/> <span class='basic_pink'> V\u1eady c\u00e1c s\u1ed1 c\u1ea7n \u0111i\u1ec1n l\u00e0: 8; 16 <\/span> <br\/><span class='basic_left'> <span class='basic_green'> <i> Nh\u1eadn x\u00e9t: Trong 1 s\u1ed1 b\u00e0i to\u00e1n, gi\u00e1 tr\u1ecb ph\u1ea3i t\u00ecm c\u00f3 th\u1ec3 kh\u00f4ng ph\u1ee5 thu\u1ed9c v\u00e0o m\u1ed9t \u0111\u1ea1i l\u01b0\u1ee3ng n\u00e0o \u0111\u00f3. Ch\u1eb3ng h\u1ea1n t\u00ecm th\u1eddi gian hai xe g\u1eb7p nhau nh\u01b0 b\u00e0i to\u00e1n tr\u00ean n\u1ebfu xe th\u1ee9 nh\u1ea5t \u0111i h\u1ebft qu\u00e3ng \u0111\u01b0\u1eddng AB m\u1ea5t 2 gi\u1edd, xe th\u1ee9 hai \u0111i h\u1ebft qu\u00e3ng \u0111\u01b0\u1eddng AB m\u1ea5t 3 gi\u1edd. G\u1ecdi qu\u00e3ng \u0111\u01b0\u1eddng AB l\u00e0 a (km) th\u00ec trong 1 gi\u1edd hai xe \u0111i \u0111\u01b0\u1ee3c: $\\dfrac{a}{2} + \\dfrac{a}{3} = \\dfrac{5a}{6}$ (km). Th\u1eddi gian \u0111\u1ec3 hai xe \u0111i h\u1ebft qu\u00e3ng \u0111\u01b0\u1eddng AB l\u00e0:$ a : \\dfrac{5a}{6} = \\dfrac{6}{5}$ (gi\u1edd). <br\/> Th\u1eddi gian n\u00e0y kh\u00f4ng ph\u1ee5 thu\u1ed9c v\u00e0o qu\u00e3ng \u0111\u01b0\u1eddng AB, n\u00ean ta c\u00f3 th\u1ec3 ch\u1ecdn qu\u00e3ng \u0111\u01b0\u1eddng AB l\u00e0 1 (\u0111\u01a1n v\u1ecb quy \u01b0\u1edbc). Khi \u0111\u00f3 1 gi\u1edd hai xe \u0111i \u0111\u01b0\u1ee3c theo th\u1ee9 t\u1ef1 l\u00e0 $\\dfrac{1}{2}$ v\u00e0 $\\dfrac{1}{3}$ qu\u00e3ng \u0111\u01b0\u1eddng AB, c\u1ea3 hai xe \u0111i \u0111\u01b0\u1ee3c: $\\dfrac{1}{2} + \\dfrac{1}{3} = \\dfrac{5}{6}$ (qu\u00e3ng \u0111\u01b0\u1eddng AB), th\u1eddi gian hai xe g\u1eb7p nhau l\u00e0: $1 : \\dfrac{5}{6} = \\dfrac{6}{5}$ (gi\u1edd) <\/i> <\/span> "}]}],"id_ques":1749},{"time":24,"part":[{"title":"\u0110i\u1ec1n \u0111\u00e1p \u00e1n \u0111\u00fang v\u00e0o \u00f4 tr\u1ed1ng","title_trans":"","temp":"fill_the_blank","correct":[[["20"]]],"list":[{"point":10,"width":50,"type_input":"","ques":"Chu vi m\u1ed9t h\u00ecnh ch\u1eef nh\u1eadt l\u00e0 18cm. N\u1ebfu gi\u1ea3m chi\u1ec1u d\u00e0i \u0111i 20%, t\u0103ng chi\u1ec1u r\u1ed9ng th\u00eam 25% th\u00ec chu vi kh\u00f4ng \u0111\u1ed5i. T\u00ednh di\u1ec7n t\u00edch c\u1ee7a h\u00ednh ch\u1eef nh\u1eadt \u0111\u00f3. <br\/> \u0110\u00e1p s\u1ed1: _input_ $cm^2$","hint":"Vi\u1ebft 20% v\u00e0 25% d\u01b0\u1edbi d\u1ea1ng ph\u00e2n s\u1ed1","explain":"<span class='basic_left'><span class='basic_green'>H\u01b0\u1edbng d\u1eabn:<\/span><br\/> <b> B\u01b0\u1edbc 1: <\/b> T\u00ednh n\u1eeda chu vi h\u00ecnh ch\u1eef nh\u1eadt <br\/> <b> B\u01b0\u1edbc 2: <\/b> Vi\u1ebft 20% v\u00e0 25% d\u01b0\u1edbi d\u1ea1ng ph\u00e2n s\u1ed1 <br\/> V\u00ec khi gi\u1ea3m 20% chi\u1ec1u d\u00e0i, t\u0103ng 25% chi\u1ec1u r\u1ed9ng chu vi kh\u00f4ng \u0111\u1ed5i n\u00ean 20% chi\u1ec1u d\u00e0i = 25% chi\u1ec1u r\u1ed9ng <br\/> <b> B\u01b0\u1edbc 3: <\/b> T\u00ednh chi\u1ec1u d\u00e0i v\u00e0i chi\u1ec1u r\u1ed9ng h\u00ecnh ch\u1eef nh\u1eadt ban \u0111\u1ea7u <br\/> <b> B\u01b0\u1edbc 4: <\/b> T\u00ednh di\u1ec7n t\u00edch h\u00ecnh ch\u1eef nh\u1eadt <\/span> <br\/><br\/> <span class='basic_green'>B\u00e0i gi\u1ea3i:<\/span><br\/> N\u1eeda chu vi h\u00ecnh ch\u1eef nh\u1eadt l\u00e0: <br\/> 18 : 2 = 9 (cm) <br\/> V\u00ec khi gi\u1ea3m chi\u1ec1u d\u00e0i 20%, t\u0103ng chi\u1ec1u r\u1ed9ng 25% th\u00ec chu vi kh\u00f4ng \u0111\u1ed5i <br\/> N\u00ean 20% chi\u1ec1u d\u00e0i b\u1eb1ng 25% chi\u1ec1u r\u1ed9ng <br\/> Hay $\\dfrac{1}{5}$ chi\u1ec1u d\u00e0i b\u1eb1ng $\\dfrac{1}{4}$ chi\u1ec1u r\u1ed9ng v\u00e0 t\u1ed5ng chi\u1ec1u d\u00e0i v\u00e0 chi\u1ec1u r\u1ed9ng l\u00e0 9cm <br\/> Chi\u1ec1u d\u00e0i h\u00ecnh ch\u1eef nh\u1eadt l\u00e0: <br\/> 9 : 9 . 5 = 5(cm) <br\/> Chi\u1ec1u r\u1ed9ng h\u00ecnh ch\u1eef nh\u1eadt l\u00e0: <br\/> 9 - 5 = 4 (cm) <br\/> Di\u1ec7n t\u00edch h\u00ecnh ch\u1eef nh\u1eadt l\u00e0: <br\/> 4 . 5 = 20 $(cm^2)$ <br\/> \u0110\u00e1p s\u1ed1: $20cm^2$ <br\/> <span class='basic_pink'> V\u1eady s\u1ed1 c\u1ea7n \u0111i\u1ec1n l\u00e0: 20 <\/span> "}]}],"id_ques":1750}],"lesson":{"save":0,"level":3}}