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4.算一算。
（1）直接写出得数。
$\frac{1}{3} × 9=$
$\frac{7}{8} ÷ \frac{7}{8}=$
$\frac{5}{6} × \frac{3}{5}=$
$\frac{5}{63} × 9=$
$1 ÷ \frac{3}{4}=$
$\frac{5}{9} × \frac{9}{5}=$
$\frac{5}{6} ÷ 12=$
$7 ÷ \frac{1}{2}=$
$\frac{9}{11} ÷ 3=$
$\frac{1}{7} ÷ \frac{7}{11}=$
$\frac{1}{5} ÷ \frac{20}{3}=$
$\frac{1}{3} × 27 × 3=$
$\frac{7}{12} × \frac{5}{14}=$
$0 × \frac{16}{3}=$
$\frac{1}{4} × 16 ÷ 2=$
$20^2=$
$0.6^2=$
$7^2=$
（1）直接写出得数。
$\frac{1}{3} × 9=$
$\frac{7}{8} ÷ \frac{7}{8}=$
$\frac{5}{6} × \frac{3}{5}=$
$\frac{5}{63} × 9=$
$1 ÷ \frac{3}{4}=$
$\frac{5}{9} × \frac{9}{5}=$
$\frac{5}{6} ÷ 12=$
$7 ÷ \frac{1}{2}=$
$\frac{9}{11} ÷ 3=$
$\frac{1}{7} ÷ \frac{7}{11}=$
$\frac{1}{5} ÷ \frac{20}{3}=$
$\frac{1}{3} × 27 × 3=$
$\frac{7}{12} × \frac{5}{14}=$
$0 × \frac{16}{3}=$
$\frac{1}{4} × 16 ÷ 2=$
$20^2=$
$0.6^2=$
$7^2=$
答案
$\frac{1}{3} × 9=3$
$\frac{7}{8} ÷ \frac{7}{8}=1$
$\frac{5}{6} × \frac{3}{5}=\frac{1}{2}$
$\frac{5}{63} × 9=\frac{5}{7}$
$1 ÷ \frac{3}{4}=\frac{4}{3}$
$\frac{5}{9} × \frac{9}{5}=1$
$\frac{5}{6} ÷ 12=\frac{5}{72}$
$7 ÷ \frac{1}{2}=14$
$\frac{9}{11} ÷ 3=\frac{3}{11}$
$\frac{1}{7} ÷ \frac{7}{11}=\frac{11}{49}$
$\frac{1}{5} ÷ \frac{20}{3}=\frac{3}{100}$
$\frac{1}{3} × 27 × 3=27$
$\frac{7}{12} × \frac{5}{14}=\frac{5}{24}$
$0 × \frac{16}{3}=0$
$\frac{1}{4} × 16 ÷ 2=2$
$20^2=400$
$0.6^2=0.36$
$7^2=49$
$\frac{7}{8} ÷ \frac{7}{8}=1$
$\frac{5}{6} × \frac{3}{5}=\frac{1}{2}$
$\frac{5}{63} × 9=\frac{5}{7}$
$1 ÷ \frac{3}{4}=\frac{4}{3}$
$\frac{5}{9} × \frac{9}{5}=1$
$\frac{5}{6} ÷ 12=\frac{5}{72}$
$7 ÷ \frac{1}{2}=14$
$\frac{9}{11} ÷ 3=\frac{3}{11}$
$\frac{1}{7} ÷ \frac{7}{11}=\frac{11}{49}$
$\frac{1}{5} ÷ \frac{20}{3}=\frac{3}{100}$
$\frac{1}{3} × 27 × 3=27$
$\frac{7}{12} × \frac{5}{14}=\frac{5}{24}$
$0 × \frac{16}{3}=0$
$\frac{1}{4} × 16 ÷ 2=2$
$20^2=400$
$0.6^2=0.36$
$7^2=49$
（2）计算下列各题，能简算的要简算。
$\frac{16}{9} ÷ 4 ÷ \frac{8}{3}$
$\frac{8}{13} ÷ \frac{8}{13} × \frac{5}{6}$
$\frac{6}{48} × 48 × \frac{7}{8}$
$15 ÷ [ ( \frac{2}{5} + \frac{3}{10} ) ÷ \frac{1}{2} ]$
$\frac{9}{23} × \frac{1}{14} + \frac{1}{14} × \frac{14}{23}$
$\frac{16}{9} ÷ 4 ÷ \frac{8}{3}$
$\frac{8}{13} ÷ \frac{8}{13} × \frac{5}{6}$
$\frac{6}{48} × 48 × \frac{7}{8}$
$15 ÷ [ ( \frac{2}{5} + \frac{3}{10} ) ÷ \frac{1}{2} ]$
$\frac{9}{23} × \frac{1}{14} + \frac{1}{14} × \frac{14}{23}$
答案
$\frac{16}{9} ÷ 4 ÷ \frac{8}{3}$
$=\frac{16}{9}×\frac{1}{4}×\frac{3}{8}$
$=\frac{4}{9}×\frac{3}{8}$
$=\frac{1}{6}$
$\frac{8}{13} ÷ \frac{8}{13} × \frac{5}{6}$
$=1×\frac{5}{6}$
$=\frac{5}{6}$
$\frac{6}{48} × 48 × \frac{7}{8}$
$=6×\frac{7}{8}$
$=\frac{21}{4}$
$15 ÷ [ ( \frac{2}{5} + \frac{3}{10} ) ÷ \frac{1}{2} ]$
$=15 ÷ [ ( \frac{4}{10} + \frac{3}{10} ) × 2 ]$
$=15 ÷ [ \frac{7}{10} × 2 ]$
$=15 ÷ \frac{7}{5}$
$=\frac{75}{7}$
$\frac{9}{23} × \frac{1}{14} + \frac{1}{14} × \frac{14}{23}$
$=\frac{1}{14}×( \frac{9}{23} + \frac{14}{23} )$
$=\frac{1}{14}×1$
$=\frac{1}{14}$
$=\frac{16}{9}×\frac{1}{4}×\frac{3}{8}$
$=\frac{4}{9}×\frac{3}{8}$
$=\frac{1}{6}$
$\frac{8}{13} ÷ \frac{8}{13} × \frac{5}{6}$
$=1×\frac{5}{6}$
$=\frac{5}{6}$
$\frac{6}{48} × 48 × \frac{7}{8}$
$=6×\frac{7}{8}$
$=\frac{21}{4}$
$15 ÷ [ ( \frac{2}{5} + \frac{3}{10} ) ÷ \frac{1}{2} ]$
$=15 ÷ [ ( \frac{4}{10} + \frac{3}{10} ) × 2 ]$
$=15 ÷ [ \frac{7}{10} × 2 ]$
$=15 ÷ \frac{7}{5}$
$=\frac{75}{7}$
$\frac{9}{23} × \frac{1}{14} + \frac{1}{14} × \frac{14}{23}$
$=\frac{1}{14}×( \frac{9}{23} + \frac{14}{23} )$
$=\frac{1}{14}×1$
$=\frac{1}{14}$
(3)化简下列各比。
$\frac{2}{3}:\frac{4}{9}$ $\frac{45}{27}:15$ $24\ \mathrm{cm}^3:0.36\ \mathrm{dm}^3$ $300\ \mathrm{dm}^2:0.2\ \mathrm{m}^2$
(4)求比值。
$\frac{3}{4}:\frac{5}{8}$ $0.9:450$ $2.5:\frac{5}{6}$ $0.36:0.48$
$\frac{2}{3}:\frac{4}{9}$ $\frac{45}{27}:15$ $24\ \mathrm{cm}^3:0.36\ \mathrm{dm}^3$ $300\ \mathrm{dm}^2:0.2\ \mathrm{m}^2$
(4)求比值。
$\frac{3}{4}:\frac{5}{8}$ $0.9:450$ $2.5:\frac{5}{6}$ $0.36:0.48$
答案
(3)化简下列各比
$\frac{2}{3}:\frac{4}{9}$
$=(\frac{2}{3}×9):(\frac{4}{9}×9)$
$=6:4$
$=3:2$
$\frac{45}{27}:15$
$=\frac{5}{3}:15$
$=(\frac{5}{3}×3):(15×3)$
$=5:45$
$=1:9$
$24\ \mathrm{cm}^3:0.36\ \mathrm{dm}^3$
$=24\ \mathrm{cm}^3:360\ \mathrm{cm}^3$
$=24:360$
$=1:15$
$300\ \mathrm{dm}^2:0.2\ \mathrm{m}^2$
$=300\ \mathrm{dm}^2:20\ \mathrm{dm}^2$
$=300:20$
$=15:1$
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(4)求比值
$\frac{3}{4}:\frac{5}{8}$
$=\frac{3}{4}÷\frac{5}{8}$
$=\frac{6}{5}$
$0.9:450$
$=0.9÷450$
$=\frac{1}{500}$
$2.5:\frac{5}{6}$
$=2.5÷\frac{5}{6}$
$=3$
$0.36:0.48$
$=0.36÷0.48$
$=\frac{3}{4}$
$\frac{2}{3}:\frac{4}{9}$
$=(\frac{2}{3}×9):(\frac{4}{9}×9)$
$=6:4$
$=3:2$
$\frac{45}{27}:15$
$=\frac{5}{3}:15$
$=(\frac{5}{3}×3):(15×3)$
$=5:45$
$=1:9$
$24\ \mathrm{cm}^3:0.36\ \mathrm{dm}^3$
$=24\ \mathrm{cm}^3:360\ \mathrm{cm}^3$
$=24:360$
$=1:15$
$300\ \mathrm{dm}^2:0.2\ \mathrm{m}^2$
$=300\ \mathrm{dm}^2:20\ \mathrm{dm}^2$
$=300:20$
$=15:1$
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(4)求比值
$\frac{3}{4}:\frac{5}{8}$
$=\frac{3}{4}÷\frac{5}{8}$
$=\frac{6}{5}$
$0.9:450$
$=0.9÷450$
$=\frac{1}{500}$
$2.5:\frac{5}{6}$
$=2.5÷\frac{5}{6}$
$=3$
$0.36:0.48$
$=0.36÷0.48$
$=\frac{3}{4}$
