《2025年超能学典江苏13大市名牌小学毕业升学真卷精编数学2版》

11. 一个两位小数去掉小数点后,与原来的小数相加和是238.36,原来的两位小数是(2.36)。

答案： 2.36

1. 直接写出得数。(8 分)
$\frac {1}{6}+\frac {1}{4}=$$\frac{5}{12}$
$\frac {2}{3}÷\frac {1}{6}=$4
$\frac {5}{6}×\frac {3}{10}=$$\frac{1}{4}$
$\frac {3}{4}-\frac {1}{5}=$$\frac{11}{20}$
$2.1×0.3=$0.63
$3.8-1.24=$2.56
$6÷15\% =$40
$0.5^{3}=$0.125

答案： $\frac{5}{12}$ 4 $\frac{1}{4}$ $\frac{11}{20}$ 0.63 2.56 40 0.125

2. 求未知数 x。(6 分)
$2x-\frac {3}{5}x= \frac {14}{15}$
$x-1= \frac {1}{2}x+\frac {1}{4}x+\frac {1}{8}x+\frac {1}{16}x+\frac {1}{32}x+\frac {1}{64}x$

答案： 1. $x=\frac{2}{3}$ 2. $x=64$

3. 下面各题,怎样简便就怎样算。(9 分)
$\frac {5}{18}÷[(\frac {7}{8}-\frac {2}{3})×\frac {4}{5}]$
$\frac {16}{7}×\frac {5}{8}-\frac {2}{7}×\frac {8}{5}$
$\frac {1}{2}+\frac {5}{6}+\frac {11}{12}+\frac {19}{20}+\frac {29}{30}+\frac {41}{42}+\frac {55}{56}$

答案： 1. $\frac{5}{3}$ 2. $\frac{34}{35}$ 3. $\frac{1}{2}+\frac{5}{6}+\frac{11}{12}+\frac{19}{20}+\frac{29}{30}+\frac{41}{42}+\frac{55}{56}=7-(\frac{1}{2}+\frac{1}{6}+\frac{1}{12}+\frac{1}{20}+\frac{1}{30}+\frac{1}{42}+\frac{1}{56})=7-(1-\frac{1}{2}+\frac{1}{2}-\frac{1}{3}+\frac{1}{3}-\frac{1}{4}+\frac{1}{4}-\frac{1}{5}+\frac{1}{5}-\frac{1}{6}+\frac{1}{6}-\frac{1}{7}+\frac{1}{7}-\frac{1}{8})=7-\frac{7}{8}=6\frac{1}{8}$