12．直接写出得数．
| $\frac{7}{12}$×$\frac{3}{5}$ | 0.9+99×0.9= | 2.5×$\frac{2}{3}$×0.4= | （$\frac{1}{2}$+$\frac{1}{3}$）×6= |
| 1-1÷$\frac{3}{2}$= | 1.02-0.43-0.57= | 20-19.02= | 2÷$\frac{2}{3}$-$\frac{2}{3}$÷2= |
7．口算我能行：
0 156542 156550 156556 156560 156566 156568 156572 156578 156580 156586 156592 156596 156598 156602 156608 156610 156616 156620 156622 156626 156628 156632 156634 156636 156637 156638 156640 156641 156642 156644 156646 156650 156652 156656 156658 156662 156668 156670 156676 156680 156682 156686 156692 156698 156700 156706 156710 156712 156718 156722 156728 156736 199269
| $\frac{4}{5}$-$\frac{3}{4}$= | $\frac{5}{12}$×4= | 6-$\frac{7}{10}$= | $\frac{2}{5}$÷$\frac{1}{5}$= | $\frac{1}{3}$+$\frac{1}{3}$×$\frac{1}{3}$= |
| $\frac{5}{12}$+$\frac{7}{24}$= | $\frac{2}{7}$×$\frac{3}{4}$= | $\frac{7}{8}$÷$\frac{7}{8}$= | $\frac{1}{4}$×$\frac{3}{8}$= | 10-$\frac{3}{4}$×$\frac{8}{9}$= |