第39页 - 通城学典课时作业本六年级数学苏教版江苏专用

$ \begin{aligned}解：4x+4.8&=15.2 \\ 4x&=10.4 \\ x&=2.6 \\ \end{aligned}$

$ \begin{aligned}解：\frac {2}{3}x&=\frac {5}{6} \\ x&=\frac {5}{4} \\ \end{aligned}$

$ \begin{aligned}解：\frac {5}{8}x&=\frac {5}{14}×21 \\ \frac {5}{8}x&=\frac {15}{2} \\ x&=12 \\ \end{aligned}$

$ \begin{aligned}解：\frac {2}{3}x&=\frac {2}{9}×21 \\ \frac {2}{3}x&=\frac {14}{3} \\ x&=7 \\ \end{aligned}$

=(772+128)−(317+283)

=900−600

=300

=(0.4×0.25)×12

=0.1×12

=1.2

=(3.8-0.9)×0.5

=2.9×0.5

=1.45

$=\frac {5}{12}×12+\frac {1}{19}×12+\frac {7}{19}$

$=5+(\frac {12}{19}+\frac {7}{19})$

$=5+1$

$=6$

=(127-26-1)×0.75

=100×0.75

=75

$ =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}$

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

$=\frac {6}{7}$

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