直接写得数. ×4= | + = | + = | ÷ = |
25÷ = | - = | ÷5= | × = |
2÷ = | - = | ×12= | 2- - = |
×4=1;
+
=
;
+
=
;
÷
=
;25÷
=45;
-
=
;
÷5=
;
×
=
;2÷
=12;
-
=
;
×12=4; 2-
-
=1.分析:(1)(8)(11)题,属于分数乘法计算,约分即可;
(2)(3)(6)(10)(12)题,属于分数的加减法计算,注意同分母与异分母分数的计算方法,其中第(12)题可运用减法的性质简算;
(4)(5)(7)(9)题,属于分数的除法计算,除以一个数等于乘这个数的倒数,能约分的要约分.
点评:考查了分数的四则运算,关键要掌握运算法则.