①在（4，2）位置上的棋子上标上字母“A”；
1．直接写得数．
0 160768 160776 160782 160786 160792 160794 160798 160804 160806 160812 160818 160822 160824 160828 160834 160836 160842 160846 160848 160852 160854 160858 160860 160862 160863 160864 160866 160867 160868 160870 160872 160876 160878 160882 160884 160888 160894 160896 160902 160906 160908 160912 160918 160924 160926 160932 160936 160938 160944 160948 160954 160962 199269
| 10÷0.01= | 1÷0.25= | 6÷0.2= | 7.5-4.5= | 4÷0.25= |
| 0÷19.8= | 0.2×0.05= | 0.6×1.5= | 1.36+2.87+3.64= | 1.8×0.4×0.25= |