第90页 - 通城学典课时作业本五年级数学苏教版江苏专用

$\frac {100}{96}$

$\frac {25}{24}$

3

5

7

4

25.12

50.24

C

A

B

C

$=\frac {1}{3}+\frac {1}{6}+\frac {1}{12}+ \frac {1}{24}+\frac {1}{48}+\frac {1}{48}-\frac {1}{48}$

$=\frac {1}{3}+\frac {1}{6}+\frac {1}{12}+ \frac {1}{24}+\frac {1}{24}−\frac {1}{48}$

$=\frac {1}{3}+\frac {1}{6}+ \frac {1}{12}+\frac {1}{12}- \frac {1}{48}$

$=\frac {1}{3}+\frac {1}{6}+\frac {1}{6}-\frac {1}{48}$

$=\frac {1}{3}+\frac {1}{3} -\frac {1}{48}$

$= \frac {2}{3}−\frac {1}{48}$

$=\frac {31}{48}$