直接写数对又快：
1÷ = |  + = |  ÷ = | （ - ）×18= |
| ÷3= | ×= |  -= |  ×÷×= |
=
．
②从正面看 
③从侧面看
直接写出得数．
| 1-×0= |  ×12+= | ×4+4×= |  ÷7+ × = |
a-a× = | 4.9+0.1-4.9+0.1= | 11a-6a+5a= |  + ÷+ = |
| 1÷= | += | ÷= | （-）×18= |
| ÷3= | ×= | -= | ×÷×= |
| 1-×0= | ×12+= | ×4+4×= | ÷7+×= |
| a-a×= | 4.9+0.1-4.9+0.1= | 11a-6a+5a= | +÷+= |