3- = | × = | 1+ = | 2- = | - = |
- - = | 3÷4+ = | 0.12÷20%= | ×4÷ ×4= | 3.2+ -3.2+ = |
解:3- =2 , | × = , | 1+ =1 , | 2- =1 , | - = , |
- - = , | 3÷4+ =1, | 0.12÷20%=0.6, | ×4÷ ×4=16, | 3.2+ -3.2+ = . |
分析:根据分数、小数和百分数的加减乘除的计算方法进行计算即可;
-
-
=
-(
+
);
×4÷
×4按照从左向右的顺序进行计算;3.2+
-3.2+
=(3.2-3.2)
+
).点评:口算时,注意运算符号和数据,然后再进一步计算即可,能简算的要简算.
=
×
=
=
=
,
,
,
.