( + ×1 )÷(4- ) | 6× +4×75% |
| 5.6×0.25 | 8×(20-1.25) |
(1)(
+
×1
)÷(4-
),=(
+1)÷(4-
),=1
÷3
,=
;(2)6×
+4×75%,=6×0.75+4×0.75,
=(6+4)×0.75,
=10×0.75,
=7.5;
(3)5.6×0.25,
=(0.7×8)×0.25,
=0.7×(8×0.25),
=0.7×2,
=1.4;
(4)8×(20-1.25),.
=8×20-8×1.25,
=160-10,
=150.
分析:(1)先算乘法,再加法和减法,最后算除法;
(2)根据乘法分配律进行简算;
(3)5.6=0.7×8,再根据乘法结合律进行简算;
(4)根据乘法分配律进行简算.
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.