× -4.6×![]() | 9.5×3.8+ ×(19× ) |
| 14×72+42×76 | . |
(1)
×
-4.6×
,=
×4.6-4.6×
,=(
-
)×4.6,=1×4.6,
=4.6;
(2)9.5×3.8+
×(19×
),=9.5×3.8+6.2×9.5,
=9.5×(3.8+6.2),
=9.5×10,
=95;
(3)14×72+42×76,
=14×(3×24)+42×76,
=(14×3)×24+42×76,
=42×24+42×76,
=42×(24+76),
=42×100,
=4200;
(4)
,=
×(95+4),=
×95+4×
,=5+
,=5
.分析:(1)根据乘法分配律进行计算;
(2)根据乘法分配律进行计算;
(3)根据乘法分配律进行计算;
(4)根据乘法分配律进行计算.
点评:四则运算,先弄清运算顺序,然后再进一步计算,能简算的要简算.