题目内容
16.怎样简便就怎样算.| 2-$\frac{4}{9}$×$\frac{3}{8}$-$\frac{5}{6}$ | $\frac{1}{15}$×($\frac{3}{8}$-$\frac{1}{6}$)×24 | $\frac{4}{5}$×$\frac{2}{3}$+$\frac{2}{3}$×$\frac{6}{5}$ |
| 2011×$\frac{2011}{2012}$ | ($\frac{5}{12}$+$\frac{3}{5}$)×12×5 | $\frac{8}{29}$×$\frac{1}{7}$×29+$\frac{6}{7}$ |
分析 (1)先算乘法,再按照减法的性质计算;
(2)按照乘法分配律计算;
(3)按照乘法分配律计算;
(4)把2011看成2012-1,再按照乘法分配律计算;
(5)按照乘法分配律计算;
(6)利用乘法交换律计算即可.
解答 解:(1)2-$\frac{4}{9}$×$\frac{3}{8}$-$\frac{5}{6}$
=2-$\frac{1}{6}$-$\frac{5}{6}$
=2-($\frac{1}{6}$+$\frac{5}{6}$)
=2-1
=1
(2)$\frac{1}{15}$×($\frac{3}{8}$-$\frac{1}{6}$)×24
=$\frac{1}{15}$×($\frac{3}{8}$×24-$\frac{1}{6}$×24)
=$\frac{1}{15}$×(9-4)
=$\frac{1}{15}$×5
=$\frac{1}{3}$
(3)$\frac{4}{5}$×$\frac{2}{3}$+$\frac{2}{3}$×$\frac{6}{5}$
=($\frac{4}{5}$+$\frac{6}{5}$)×$\frac{2}{3}$
=2×$\frac{2}{3}$
=$\frac{4}{3}$
(4)2011×$\frac{2011}{2012}$
=(2012-1)×$\frac{2011}{2012}$
=2012×$\frac{2011}{2012}$-$\frac{2011}{2012}$
=2011-$\frac{2011}{2012}$
=2010$\frac{1}{2012}$
(5)($\frac{5}{12}$+$\frac{3}{5}$)×12×5
=$\frac{5}{12}$×12×5+$\frac{3}{5}$×12×5
=25+36
=61
(6)$\frac{8}{29}$×$\frac{1}{7}$×29+$\frac{6}{7}$
=$\frac{8}{29}$×29×$\frac{1}{7}$+$\frac{6}{7}$
=8×$\frac{1}{7}$+$\frac{6}{7}$
=$\frac{8}{7}$+$\frac{6}{7}$
=2
点评 本题考查了四则混合运算,注意运算顺序和运算法则,灵活运用所学的运算定律进行简便计算.
| A. | $\frac{2}{3}$×$\frac{3}{8}$ | B. | $\frac{2}{3}$×$\frac{3}{7}$ | C. | $\frac{2}{3}$×$\frac{5}{3}$ |