1.口算。
$0.25×40=$ $180÷0.6=$ $25.45−0.8=$ $0.5−\frac{1}{4}=$
$0.2^{2}=$ $0.43+67\%=$ $\frac{1}{2}+\frac{3}{4}=$ $0.6÷\frac{3}{4}=$
$3\pi\approx$ $12÷1\%=$ $\frac{2}{3}×\frac{3}{8}=$ $\frac{1}{3}-\frac{1}{4}=$
$0.25×\frac{1}{4}×0.8=$ $4.3+5.7+\frac{1}{2}=$ $8.4×\frac{1}{3}-\frac{1}{3}×2.4=$
$0.25×40=$ $180÷0.6=$ $25.45−0.8=$ $0.5−\frac{1}{4}=$
$0.2^{2}=$ $0.43+67\%=$ $\frac{1}{2}+\frac{3}{4}=$ $0.6÷\frac{3}{4}=$
$3\pi\approx$ $12÷1\%=$ $\frac{2}{3}×\frac{3}{8}=$ $\frac{1}{3}-\frac{1}{4}=$
$0.25×\frac{1}{4}×0.8=$ $4.3+5.7+\frac{1}{2}=$ $8.4×\frac{1}{3}-\frac{1}{3}×2.4=$
答案:
10 300 24.65 $\frac{1}{4}$ 0.04 1.1 $\frac{5}{4}$ 0.8 9.42 1200 $\frac{1}{4}$ $\frac{1}{12}$ 0.05 10.5 2
2.脱式计算。
$20×3.14−3.14×14$ $8.5−(5.6+4.8)÷1.3$ $43×102$
$\frac{4}{5}+\frac{2}{3}-\frac{1}{6}$ $\frac{3}{4}×\frac{1}{3}×5$ $5×\frac{2}{7}+5×\frac{5}{7}$
$(\frac{1}{8}+\frac{1}{4})÷\frac{1}{16}=$ $8-\frac{2}{3}÷\frac{1}{4}-\frac{4}{3}$ $12×(\frac{1}{6}+\frac{1}{4}-\frac{1}{3})$
$20×3.14−3.14×14$ $8.5−(5.6+4.8)÷1.3$ $43×102$
$\frac{4}{5}+\frac{2}{3}-\frac{1}{6}$ $\frac{3}{4}×\frac{1}{3}×5$ $5×\frac{2}{7}+5×\frac{5}{7}$
$(\frac{1}{8}+\frac{1}{4})÷\frac{1}{16}=$ $8-\frac{2}{3}÷\frac{1}{4}-\frac{4}{3}$ $12×(\frac{1}{6}+\frac{1}{4}-\frac{1}{3})$
答案:
$20×3.14 - 3.14×14$
$=3.14×(20 - 14)$
$=3.14×6$
$=18.84$
$8.5 - (5.6 + 4.8)÷1.3$
$=8.5 - 10.4÷1.3$
$=8.5 - 8$
$=0.5$
$43×102$
$=43×(100 + 2)$
$=43×100 + 43×2$
$=4300 + 86$
$=4386$
$\frac{4}{5} + \frac{2}{3} - \frac{1}{6}$
$=\frac{4}{5} + \frac{4}{6} - \frac{1}{6}$
$=\frac{4}{5} + \frac{1}{2}$
$=\frac{8}{10} + \frac{5}{10}$
$=\frac{13}{10}$
$\frac{3}{4}×\frac{1}{3}×5$
$=\frac{1}{4}×5$
$=\frac{5}{4}$
$5×\frac{2}{7} + 5×\frac{5}{7}$
$=5×1$
$=5$
$(\frac{1}{8} + \frac{1}{4})÷\frac{1}{16}$
$=\frac{1}{8}×16 + \frac{1}{4}×16$
$=2 + 4$
$=6$
$8 - \frac{2}{3}÷\frac{1}{4} - \frac{4}{2}$
$=8 - \frac{2}{3}×4 - \frac{4}{3}$
$=8 - \frac{8}{3} - \frac{4}{3}$
$=4$
$12×(\frac{1}{6} + \frac{1}{4} - \frac{1}{3})$
$=12×\frac{1}{6} + 12×\frac{1}{4} - 12×\frac{1}{3}$
$=2 + 3 - 4$
$=1$
$=3.14×(20 - 14)$
$=3.14×6$
$=18.84$
$8.5 - (5.6 + 4.8)÷1.3$
$=8.5 - 10.4÷1.3$
$=8.5 - 8$
$=0.5$
$43×102$
$=43×(100 + 2)$
$=43×100 + 43×2$
$=4300 + 86$
$=4386$
$\frac{4}{5} + \frac{2}{3} - \frac{1}{6}$
$=\frac{4}{5} + \frac{4}{6} - \frac{1}{6}$
$=\frac{4}{5} + \frac{1}{2}$
$=\frac{8}{10} + \frac{5}{10}$
$=\frac{13}{10}$
$\frac{3}{4}×\frac{1}{3}×5$
$=\frac{1}{4}×5$
$=\frac{5}{4}$
$5×\frac{2}{7} + 5×\frac{5}{7}$
$=5×1$
$=5$
$(\frac{1}{8} + \frac{1}{4})÷\frac{1}{16}$
$=\frac{1}{8}×16 + \frac{1}{4}×16$
$=2 + 4$
$=6$
$8 - \frac{2}{3}÷\frac{1}{4} - \frac{4}{2}$
$=8 - \frac{2}{3}×4 - \frac{4}{3}$
$=8 - \frac{8}{3} - \frac{4}{3}$
$=4$
$12×(\frac{1}{6} + \frac{1}{4} - \frac{1}{3})$
$=12×\frac{1}{6} + 12×\frac{1}{4} - 12×\frac{1}{3}$
$=2 + 3 - 4$
$=1$
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