一、在$◯$里填“＞”“＜”或“=”。
$\frac {2}{3}×\frac {4}{5}$$\frac {2}{3}$
$2×\frac {1}{2}$$1×\frac {1}{2}$
$\frac {2}{3}×\frac {3}{2}$$5×\frac {1}{5}$
$\frac {4}{13}×\frac {6}{5}$$\frac {4}{13}$
$\frac {8}{11}×\frac {1}{4}$$\frac {4}{11}×\frac {1}{2}$
$\frac {5}{6}×\frac {6}{5}$$\frac {3}{7}×\frac {7}{3}$
$\frac {17}{10}×\frac {3}{7}$$\frac {17}{10}$
$\frac {7}{4}×1$$\frac {7}{4}×\frac {1}{2}$
$\frac {1}{11}×10$$\frac {1}{10}×11$

＜ ＞ = ＞ = = ＜ ＞ ＜

$\frac{2}{3}×\frac{4}{5}＜\frac{2}{3}$
$2×\frac{1}{2}＞1×\frac{1}{2}$
$\frac{2}{3}×\frac{3}{2}=5×\frac{1}{5}$
$\frac{4}{13}×\frac{6}{5}＞\frac{4}{13}$
$\frac{8}{11}×\frac{1}{4}=\frac{4}{11}×\frac{1}{2}$
$\frac{5}{6}×\frac{6}{5}=\frac{3}{7}×\frac{7}{3}$
$\frac{17}{10}×\frac{3}{7}＜\frac{17}{10}$
$\frac{7}{4}×1＞\frac{7}{4}×\frac{1}{2}$
$\frac{1}{11}×10＜\frac{1}{10}×11$

二、连一连。

三、计算下面各题。
$\frac {3}{4}×\frac {5}{9}×\frac {2}{15}$
$15×\frac {3}{20}×\frac {4}{9}$
$\frac {3}{4}×\frac {6}{11}×\frac {2}{21}$
$\frac {4}{21}×\frac {9}{25}×\frac {35}{48}$
$\frac {7}{9}×\frac {3}{5}×\frac {5}{21}$
$\frac {35}{48}×\frac {8}{15}×\frac {6}{7}$
$\frac {40}{13}×\frac {7}{80}×39$
$\frac {5}{12}×\frac {8}{25}×\frac {3}{4}$
$\frac {27}{10}×\frac {5}{3}×\frac {5}{2}$
$12×\frac {3}{4}×\frac {4}{7}$
$\frac {3}{5}×\frac {1}{6}×\frac {5}{7}$
$21×\frac {5}{14}×\frac {8}{5}$
$\frac {5}{7}×\frac {28}{13}×\frac {2}{7}$
$\frac {2}{3}×\frac {13}{8}×\frac {4}{39}$
$\frac {4}{5}×4×\frac {7}{18}$
$\frac {19}{20}×\frac {4}{9}×\frac {25}{38}$
$\frac {5}{8}×\frac {2}{3}×\frac {8}{15}$
$\frac {3}{16}×\frac {1}{4}×\frac {8}{27}$
$\frac {5}{33}×22×\frac {1}{5}$
$\frac {7}{15}×\frac {3}{8}×\frac {5}{21}$
$\frac {5}{12}×\frac {15}{16}×\frac {24}{25}$

$\frac{1}{18}$ 1 $\frac{3}{77}$ $\frac{1}{20}$ $\frac{1}{9}$ $\frac{1}{3}$ $\frac{21}{2}$ $\frac{1}{10}$ $\frac{45}{4}$ $\frac{36}{7}$ $\frac{1}{14}$ 12 $\frac{40}{91}$ $\frac{1}{9}$ $\frac{56}{45}$ $\frac{5}{18}$ $\frac{2}{9}$ $\frac{1}{72}$ $\frac{2}{3}$ $\frac{1}{24}$ $\frac{3}{8}$

1. $\frac{3}{4}×\frac{5}{9}×\frac{2}{15}$
$=\frac{3×5×2}{4×9×15}$
$=\frac{30}{540}$
$=\frac{1}{18}$
2. $15×\frac{3}{20}×\frac{4}{9}$
$=\frac{15×3×4}{20×9}$
$=\frac{180}{180}$
$=1$
3. $\frac{3}{4}×\frac{6}{11}×\frac{2}{21}$
$=\frac{3×6×2}{4×11×21}$
$=\frac{36}{924}$
$=\frac{3}{77}$
4. $\frac{4}{21}×\frac{9}{25}×\frac{35}{48}$
$=\frac{4×9×35}{21×25×48}$
$=\frac{1260}{25200}$
$=\frac{1}{20}$
5. $\frac{7}{9}×\frac{3}{5}×\frac{5}{21}$
$=\frac{7×3×5}{9×5×21}$
$=\frac{105}{945}$
$=\frac{1}{9}$
6. $\frac{35}{48}×\frac{8}{15}×\frac{6}{7}$
$=\frac{35×8×6}{48×15×7}$
$=\frac{1680}{5040}$
$=\frac{1}{3}$
7. $\frac{40}{13}×\frac{7}{80}×39$
$=\frac{40×7×39}{13×80}$
$=\frac{10920}{1040}$
$=\frac{21}{2}$
8. $\frac{5}{12}×\frac{8}{25}×\frac{3}{4}$
$=\frac{5×8×3}{12×25×4}$
$=\frac{120}{1200}$
$=\frac{1}{10}$
9. $\frac{27}{10}×\frac{5}{3}×\frac{5}{2}$
$=\frac{27×5×5}{10×3×2}$
$=\frac{675}{60}$
$=\frac{45}{4}$
10. $12×\frac{3}{4}×\frac{4}{7}$
$=\frac{12×3×4}{4×7}$
$=\frac{144}{28}$
$=\frac{36}{7}$
11. $\frac{3}{5}×\frac{1}{6}×\frac{5}{7}$
$=\frac{3×1×5}{5×6×7}$
$=\frac{15}{210}$
$=\frac{1}{14}$
12. $21×\frac{5}{14}×\frac{8}{5}$
$=\frac{21×5×8}{14×5}$
$=\frac{840}{70}$
$=12$
13. $\frac{5}{7}×\frac{28}{13}×\frac{2}{7}$
$=\frac{5×28×2}{7×13×7}$
$=\frac{280}{637}$
$=\frac{40}{91}$
14. $\frac{2}{3}×\frac{13}{8}×\frac{4}{39}$
$=\frac{2×13×4}{3×8×39}$
$=\frac{104}{936}$
$=\frac{1}{9}$
15. $\frac{4}{5}×4×\frac{7}{18}$
$=\frac{4×4×7}{5×18}$
$=\frac{112}{90}$
$=\frac{56}{45}$
16. $\frac{19}{20}×\frac{4}{9}×\frac{25}{38}$
$=\frac{19×4×25}{20×9×38}$
$=\frac{1900}{6840}$
$=\frac{5}{18}$
17. $\frac{5}{8}×\frac{2}{3}×\frac{8}{15}$
$=\frac{5×2×8}{8×3×15}$
$=\frac{80}{360}$
$=\frac{2}{9}$
18. $\frac{3}{16}×\frac{1}{4}×\frac{8}{27}$
$=\frac{3×1×8}{16×4×27}$
$=\frac{24}{1728}$
$=\frac{1}{72}$
19. $\frac{5}{33}×22×\frac{1}{5}$
$=\frac{5×22×1}{33×5}$
$=\frac{110}{165}$
$=\frac{2}{3}$
20. $\frac{7}{15}×\frac{3}{8}×\frac{5}{21}$
$=\frac{7×3×5}{15×8×21}$
$=\frac{105}{2520}$
$=\frac{1}{24}$
21. $\frac{5}{12}×\frac{15}{16}×\frac{24}{25}$
$=\frac{5×15×24}{12×16×25}$
$=\frac{1800}{4800}$
$=\frac{3}{8}$