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222-9+11+12:2*14+14 = ? ( )

Toán Lớp 7: 1. Tính nhanh a. -13/25 . 5/64 – 25/-13 . (-64) b. -9/13 . 5/17 + -17/13 . 5/17 – 2021 c. 4/15 – 3/7 + 11/15 – 4/7 d. (-5/6 + 2/5) : 3/

Toán Lớp 7: 1. Tính nhanh
a. -13/25 . 5/64 – 25/-13 . (-64)
b. -9/13 . 5/17 + -17/13 . 5/17 – 2021
c. 4/15 – 3/7 + 11/15 – 4/7
d. (-5/6 + 2/5) : 3/8 + (4/15 = 11/50) : 3/8

Comments ( 1 )

  1. Giải đáp:
    $a. – \frac{147}{2080}$
    $b. – \frac{34367}{17}$
    $c. 0$
    $d. \frac{32}{225}$
    Lời giải và giải thích chi tiết:
    $a. – \frac{13}{25}.\frac{5}{64} – \frac{25}{-13.(-64)}$
    $= – \frac{13}{5.64} – \frac{25}{13.64}$
    $= – \frac{1}{64}( \frac{13}{5} + \frac{25}{13} )$
    $= – \frac{1}{64}( \frac{169}{65} + \frac{125}{65} )$
    $= – \frac{1}{64}.\frac{294}{65}$
    $= – \frac{147}{2080}$
    $b. – \frac{9}{13}.\frac{5}{17} – \frac{17}{13}.\frac{5}{17} – 2021$
    $= \frac{5}{17}( – \frac{9}{13} – \frac{17}{13} ) – 2021$
    $= \frac{5}{17}.\frac{-26}{13} – 2021$
    $= – \frac{10}{17} – 2021$
    $= – \frac{10}{17} – \frac{34357}{17}$
    $= – \frac{34367}{17}$
    $c. \frac{4}{15} – \frac{3}{7} + \frac{11}{15} – \frac{4}{7}$
    $= ( \frac{4}{15} + \frac{11}{15} ) – ( \frac{3}{7} + \frac{4}{7} )$
    $= \frac{15}{15} – \frac{7}{7}$
    $= 1 – 1$
    $= 0$
    $d. ( – \frac{5}{6} + \frac{2}{5} ) : \frac{3}{8} + ( \frac{4}{15} + \frac{11}{50} ) : \frac{3}{8}$
    $= ( – \frac{5}{6} + \frac{2}{5} + \frac{4}{15} + \frac{11}{50} ) : \frac{3}{8}$
    $= ( – \frac{125}{150} + \frac{60}{150} + \frac{40}{150} + \frac{33}{150} ) . \frac{8}{3}$
    $= \frac{8}{150} . \frac{8}{3}$
    $= \frac{4}{75} . \frac{8}{3}$
    $= \frac{32}{225}$

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222-9+11+12:2*14+14 = ? ( )