| 1.45×5= | ×2.4= | ×3÷ = | 1.6×0.125= |
| 4.7×9+4.7= | 1.25×6.3×8= | 6.5×2÷5= | 15÷ × = |
×2÷ ×2= | 1÷ - ÷1= |
| 解:1.45×5=7.25, | ×2.4=1.6, | ×3÷ =3, | 1.6×0.125=0.2, |
| 4.7×9+4.7=47, | 1.25×6.3×8=63, | 6.5×2÷5=2.6, | 15÷ × =15, |
×2÷ ×2=4, | 1÷ - ÷1=2 . |
.分析:1.45×5直接用小数乘法计算的方法求解;
×2.4直接用2.4和3约分求解;
×3÷
先把除法变成乘法,再运用乘法交换律简算;1.6×0.125先把1.6分解成0.2×8再运用乘法结合律简算;
4.7×9+4.7运用乘法分配律简算;
1.25×6.3×8运用乘法交换律简算;
6.5×2÷5先算乘法,再算除法;
15÷
×
先把除法变成乘法,再运用乘法结合律简算;
×2÷
×2先把除法变成乘法,再运用乘法交换律简算;1÷
-
÷1先同时运算除法,再算减法.点评:运算定律是常用的简便运算的方法,要熟练掌握,灵活运用.