第49页 - 亮点给力提优课时作业本五年级数学江苏版

$\frac{2}{3}$

$1 {\frac{3} {10}}$

$\frac{3}{2}$

$6\frac{1}{3}$

$\frac{5}{7}$

$\frac{31} {20}$

$\frac{1}{3}$

16

$=\frac {20}{30}+\frac {24}{30}-\frac {9}{30}$

$=\frac {22}{15}-\frac {9}{30}$

$=\frac {7}{6}$

$=\frac {7}{10}+\frac {3}{10}-\frac {3}{7}$

$=1-\frac {3}{7}$

$= \frac {4}{7}$

$=(\frac {7}{6}+\frac {5}{6})-(\frac {3}{10}+\frac {3}{10})$

$=2-\frac {3}{5}$

$=1 \frac {2}{5}$

$=(\frac {7}{8}+\frac {1}{8})+(\frac {2}{5}+\frac {3}{5})$

$=1+1$

$=2$

$=(\frac {11}{8}-\frac {3}{8})-(\frac {5}{6}+\frac {1}{6})$

$=1-1$

$=0$

$=1-\frac {1}{32}$

$=\ \frac {31}{32}$

$ \begin{aligned}解：4.7x&=23.5 \\ x&=5 \\ \end{aligned}$

$ \begin{aligned}解：5x&=1 \\ x&=\frac {1}{5} \\ \end{aligned}$

$ \begin{aligned}解：8x-8&=50 \\ 8x&=58 \\ x&=7.25 \\ \end{aligned}$

$周长:2×2× 3.14÷4×2+(4−2)×4=14.28(\ \mathrm {cm})\ $

$面积:4×4−3.14×2^{2}÷4×2=9.72({c m^{2}})$

$周长:3.14×8÷2+8=20.56(\ \mathrm {cm})\ $

$3.14×(8÷2)+20.56=33.12(\ \mathrm {cm})\ $

$面积:3.14×( 8 ÷2 )^{2}÷2$

$−3.14×(8÷2 ÷2 )^{2}=12.56({c m^{2}})$