Cộng, trừ, nhân, chia số hữu tỉ

Home Lớp 7 Toán lớp 7 - Sách kết nối tri thức Bài 2: Cộng, trừ, nhân, chia số hữu tỉBài tập nâng cao

{"common":{"save":0,"post_id":"5644","level":3,"total":10,"point":10,"point_extra":0},"segment":[{"id":"6816","post_id":"5644","mon_id":"1158532","chapter_id":"1158544","question":"Gi\u1ea3 s\u1eed m\u1ed9t khinh khí c\u1ea7u bay lên t\u1eeb m\u1eb7t \u0111\u1ea5t theo chi\u1ec1u th\u1eb3ng \u0111\u1ee9ng v\u1edbi v\u1eadn t\u1ed1c 0,8 m\/s trong 60 giây. Sau \u0111ó nó gi\u1ea3m d\u1ea7n \u0111\u1ed9 cao v\u1edbi v\u1eadn t\u1ed1c $\\dfrac{5}{8}$<\/span> m\/s. H\u1ecfi sau 16 giây k\u1ec3 t\u1eeb lúc h\u1ea1 \u0111\u1ed9 cao, khinh khí c\u1ea7u còn cách m\u1eb7t \u0111\u1ea5t bao nhiêu mét?<\/p>","options":["A.<\/strong> 38 m","B.<\/strong> 16 m","C. <\/strong>10 m","D.<\/strong> 48 m"],"correct":"1","level":"3","hint":"","answer":"Trong 60 giây \u0111\u1ea7u, khinh khí c\u1ea7u bay lên cách m\u1eb7t \u0111\u1ea5t là<\/p>$0,8.60 = 48$<\/span> (m)<\/p>Sau 16 giây, khinh khí c\u1ea7u gi\u1ea3m \u0111\u1ed9 cao là<\/p> $\\dfrac{5}{8}$<\/span> . 16 = 10 (m)<\/p>V\u1eady sau 16 giây, khinh khí c\u1ea7u còn cách m\u1eb7t \u0111\u1ea5t là  48 - 10 = 38 (m)<\/p>\u0110áp án \u0111úng là   A.<\/strong> 38 m<\/span><\/p>","type":"choose","extra_type":"classic","time":"0","user_id":"131","test":"1","date":"2022-03-31 09:26:26","option_type":"txt","len":0},{"id":"6818","post_id":"5644","mon_id":"1158532","chapter_id":"1158544","question":"So sánh M và 1 bi\u1ebft <\/p>$\\dfrac{4}{5}-\\left(\\dfrac{-2}{7}\\right)-\\dfrac{7}{10}+0,5$<\/span><\/p>","options":["A.<\/strong> M = 1","B.<\/strong> M > 1","C.<\/strong> M < 1"],"correct":"3","level":"3","hint":"","answer":"M = $\\dfrac{4}{5}-\\left(\\dfrac{-2}{7}\\right)-\\dfrac{7}{10}+0,5$<\/span><\/p>M = $\\dfrac{4}{5}+\\dfrac{2}{7}-\\dfrac{7}{10}+\\dfrac{1}{2}$<\/span><\/p>M = $\\dfrac{56}{70}+\\dfrac{20}{70}-\\dfrac{49}{70}+\\dfrac{35}{70}$<\/span><\/p>M = $\\dfrac{56+20-49+35}{70}$<\/span><\/p>M = $\\dfrac{62}{70}$<\/span><\/p>M = $\\dfrac{31}{35}$<\/span><\/p>Vì $\\dfrac{31}{35}<\\dfrac{35}{35}=1$<\/span> nên M < 1.<\/p>\u0110áp án \u0111úng là   C.<\/strong> M < 1<\/span><\/p>","type":"choose","extra_type":"classic","time":"0","user_id":"131","test":"1","date":"2022-03-31 09:39:22","option_type":"txt","len":1},{"id":"6819","post_id":"5644","mon_id":"1158532","chapter_id":"1158544","question":"Tính m\u1ed9t cách h\u1ee3p lí<\/p>-0,25 . 91 + $1\\dfrac{3}{5}$<\/span> . 2023 - 0,75 . 91 - 1,6 . 2023 = <input class=\"tim_x input_number\" tpl=\"dien_so\" type=\"text\"\/><\/p>","options":"","correct":["[\"-91\"]"],"level":"3","hint":"","answer":"-0,25 . 91 + $1\\dfrac{3}{5}$<\/span> . 2023 - 0,75 . 91 - 1,6 . 2023<\/p>= -0,25 . 91 - 0,75 . 91 +  $1\\dfrac{3}{5}$<\/span> . 2023 - 1,6 . 2023<\/p>= -91 . (0,25 + 0,75) + 2023 . ( $1\\dfrac{3}{5}$<\/span> - 1,6)<\/p>= -91 . 1 + 2023 . ( $\\dfrac{8}{5}$<\/span> - $\\dfrac{16}{10}$<\/span> )<\/p>= -91 + 2023 . ( $\\dfrac{8}{5}$<\/span> - $\\dfrac{8}{5}$<\/span> )<\/p>= -91 + 2023 . 0<\/p>= -91<\/p>S\u1ed1 c\u1ea7n \u0111i\u1ec1n là  -91<\/span><\/p>","type":"blank","extra_type":"","time":"0","user_id":"131","test":"1","date":"2022-03-31 09:45:37"}]}