一、口算。
$4.84÷2=$
$0.12×30=$
$(3.6+0.4)×9=$
$310×9=$
$118-52=$
$3.7×9+3.7=$
$0.66+0.44=$
$2.5-0.59=$
$2.1-2.1÷3=$
$268÷4=$
$35+130=$
$1.2×0.4×2.5=$
$0.75×\frac{1}{2}=$
$\frac{39}{50}÷\frac{13}{15}=$
$24×(\frac{1}{4}-\frac{1}{6})=$
$\frac{2}{3}-\frac{2}{15}=$
$\frac{4}{5}÷\frac{6}{25}=$
$\frac{2}{5}+\frac{3}{5}×2=$
$\frac{3}{4}+\frac{2}{7}=$
$\frac{15}{91}×\frac{13}{20}=$
$\frac{15}{7}-(\frac{3}{4}+\frac{8}{7})=$
$12-\frac{3}{8}=$
$\frac{5}{6}÷\frac{1}{20}=$
$25÷(\frac{1}{2}-\frac{1}{3})=$

1. 2.42
2. 3.6
3. 36
4. 2790
5. 66
6. 37
7. 1.1
8. 1.91
9. 1.4
10. 67
11. 165
12. 1.2
13. $\frac{3}{8}$
14. $\frac{9}{10}$
15. 2
16. $\frac{8}{15}$
17. $\frac{10}{3}$
18. $\frac{8}{5}$
19. $\frac{29}{28}$
20. $\frac{3}{28}$
21. $\frac{1}{4}$
22. $11\frac{5}{8}$
23. $\frac{50}{3}$
24. 150

二、计算下面各题，能简算的要简算。
$\frac{4}{5}÷\frac{5}{6}÷\frac{6}{7}÷\frac{7}{8}$ $(\frac{11}{12}+\frac{7}{18}+\frac{5}{24})×72$ $(\frac{1}{2}+\frac{1}{3})÷\frac{3}{5}-\frac{17}{18}$
$7.9×11 - 7.9$ $504÷3.2×2.08 - 7.86$ $4.2×(6.18 - 3.03) + 6.5$

1. $\frac{32}{25}$
2. 109
3. $\frac{4}{9}$
4. 79
5. 319.74
6. 19.73