×12= | ÷ = | × = | ÷ = | ÷1= | - = |
+ = | 20÷ = | ×21= | ÷ = | 2÷10%= | 16×25%= |
解:
×12=6, | ÷ = , | × = , | ÷ =1, | ÷1= , | - = , |
+ = , | 20÷ =25, | ×21=9, | ÷ = , | 2÷10%=20, | 16×25%=4. |
故答案为:6,
,
,1,
,
,
,25,9,
,20,4.
分析:分数乘法:分子相乘的积做分子,分母相乘的积做分母;
分数除法:除以一个数等于乘这个数的倒数.
点评:本题考查了分数的乘除法,计算时要细心,把结果化成最简分数.
×12=
÷
×
÷
-
=
+
=
×21=
÷
=
,