1 - +0.8= | 7.4-(1 + )= | 1 - - = | 1.25×7×8= | 12 ÷3= |
| 0.25×0.4= | 4.4-3 = | 4÷0.25= | 3÷10%= | 11 ×6= |
+1÷2 = | ×(1- )= | 2×0.75= | ÷ = | 5÷25÷0.4= |
0.8× ×5= | ÷ × = | (0.18+ )÷9= | × ÷ × = | × ÷ = |
-
+0.8=1
; 7.4-(1
+
)=5.75; 1
-
-
=
; 1.25×7×8=70; 12
÷3=4
;0.25×0.4=0.1; 4.4-3
=1; 4÷0.25=16; 3÷10%=30; 11
×6=68
;
+1÷2
=
;
×(1-
)=
; 2×0.75=1.5;
÷
=
; 5÷25÷0.4=0.5;0.8×
×5=2.4;
÷
×
=
; (0.18+
)÷9=
;
×
÷
×
=
;
×
÷
=
.分析:(1)运用加法交换律与结合律简算;(2)把分数化为小数,先算括号内的,再算括号外的;(3)运用减法的性质简算;(4)运用乘法交换律与结合律简算;(5)把12
看作12+
,运用除法的性质简算;(6)(13)先算25×4,2×75然后在结果中从后向前数出两位,点上小数点;(7)把分数化为小数,再计算;(8)把被除数和除数分别扩大100倍;(9)把百分数化为小数,再计算;(10)把带分数拆成整数+分数的形式,运用乘法分配律简算;(11)先算除法;再算加法;(12)(18)先算括号内的,再算括号外的;(14)(17)(19)(20)把除法改为乘法约分计算;(15)运用除法的性质简算;(16)约分计算.点评:此题考查了多方面的知识,根据不同题目,灵活计算.