Tính bằng cách thuận tiện nhất a,3/8×2/3+5/8×2/3 b,7/15+9/16+8/15+7/16 12/11/2021 Bởi Adalyn Tính bằng cách thuận tiện nhất a,3/8×2/3+5/8×2/3 b,7/15+9/16+8/15+7/16
a,3/8×2/3+5/8×2/3 = $\frac{2}{3}$ x ($\frac{3}{8}$ + $\frac{5}{8}$ ) = $\frac{2}{3}$ x 1 = $\frac{2}{3}$ b,7/15+9/16+8/15+7/16 = ($\frac{7}{15}$ + $\frac{8}{15}$ ) + ($\frac{9}{16}$ + $\frac{7}{16}$ ) = 1 + 1 =2 Bình luận
⇒ $a )$ $\dfrac{3}{8} × \dfrac{2}{3} + \dfrac{5}{8} × \dfrac{2}{3}$ $= \dfrac{2}{3} × ( \dfrac{3}{8} + \dfrac{5}{8} )$ $=\dfrac{2}{3} × 1$ $=\dfrac{2}{3} $ $b )$ $\dfrac{7}{15} + \dfrac{9}{16} + \dfrac{8}{15} + \dfrac{7}{16}$ $= ( \dfrac{7}{15} + \dfrac{8}{15} ) + ( \dfrac{9}{16} + \dfrac{7}{16} )$ $= 1 + 1$ $= 2$ Bình luận
a,3/8×2/3+5/8×2/3
= $\frac{2}{3}$ x ($\frac{3}{8}$ + $\frac{5}{8}$ )
= $\frac{2}{3}$ x 1
= $\frac{2}{3}$
b,7/15+9/16+8/15+7/16
= ($\frac{7}{15}$ + $\frac{8}{15}$ ) + ($\frac{9}{16}$ + $\frac{7}{16}$ )
= 1 + 1
=2
⇒
$a )$ $\dfrac{3}{8} × \dfrac{2}{3} + \dfrac{5}{8} × \dfrac{2}{3}$
$= \dfrac{2}{3} × ( \dfrac{3}{8} + \dfrac{5}{8} )$
$=\dfrac{2}{3} × 1$
$=\dfrac{2}{3} $
$b )$ $\dfrac{7}{15} + \dfrac{9}{16} + \dfrac{8}{15} + \dfrac{7}{16}$
$= ( \dfrac{7}{15} + \dfrac{8}{15} ) + ( \dfrac{9}{16} + \dfrac{7}{16} )$
$= 1 + 1$
$= 2$