| 计算下面各题,能简便的要简便. 0.35×101 | 43-( +24÷ ) |
2.125× +1.875÷4 | 3÷ - ÷3 |
| 0.4×(4.7-3.65) | 12.5×2.6×0.8. |
=0.35×(100+1),
=35+0.35,
=35.35;
(2)43-(
+24÷
),=43-(0.6+24×
),=43-(0.6+9),
=43-9-0.6,
=33.4;
(3)2.125×
+1.875÷4,=2.125×
+1.875×
,=(2.125+1.875)×
,=4×
,=1;
(4)3÷
-
÷3,=3×4-
×
,=12-
,=11
;(5)0.4×(4.7-3.65),
=0.4×1.05,
=0.42;
(6)12.5×2.6×0.8,
=(12.5×0.8)×2.6,
=10×2.6,
=26.
分析:(1)把101看作100+1,运用乘法分配律简算;
(2)先算括号内的除法,把
化为小数,运用减法的性质简算;(3)把除法改为乘法,运用乘法分配律简算;
(4)先算除法,再算减法;
(5)先算括号内的,再算括号外的;
(6)运用乘法交换律与结合律简算.
点评:考查了运算定律与简便运算,四则混合运算.注意运算顺序和运算法则,灵活运用所学的运算律简便计算.