![]() | ÷[ ×( - )] | ![]() |
| 7.2×1.8+72×0.12 | × - ÷8 | . |
×
+
÷9,=
×
+
×
,=(
+
)×
,=1×
,=
;(2)
÷[
×(
-
)],=
÷[
×
],=
÷
,=
;(3)63×(
+
),=63×
+63×
,=28+45,
=73;
(4)7.2×1.8+72×0.12,
=7.2×1.8+7.2×1.2,
=7.2×(1.8+1.2),
=7.2×3,
=21.6;
(5)
×
-
÷8,=
×
-
×
,=(
-
)×
,=
×
,=
;(6)
,=(
+
)-(
+
),=1-1,
=0.
分析:(1)根据乘法分配律进行计算;
(2)先算减法,再算乘法,最后算除法;
(3)根据乘法分配律进行计算;
(4)根据乘法分配律进行计算;
(5)根据乘法分配律进行计算;
(6)根据加法交换律和结合律进行计算.
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.

