20．直接写出得数．
0 157804 157812 157818 157822 157828 157830 157834 157840 157842 157848 157854 157858 157860 157864 157870 157872 157878 157882 157884 157888 157890 157894 157896 157898 157899 157900 157902 157903 157904 157906 157908 157912 157914 157918 157920 157924 157930 157932 157938 157942 157944 157948 157954 157960 157962 157968 157972 157974 157980 157984 157990 157998 199269
| 0.3÷2= | 0.32÷0.04= | 2.64÷1.1= | 1.25×8= |
| 13.28-2.8= | 4.36+18.6= | 4.3+5.7÷1.9= | 2.5-2.5÷5= |