题目内容
能简便的用简便方法计算.
(12.5-7.6)×(3-2.8) | 7.8×101-7.8 | 7×(![]() ![]() | ![]() ![]() ![]() ![]() |
解:
(1)(12.5-7.6)×(3-2.8),
=4.9×0.2,
=0.98;
(2)7.8×101-7.8,
=7.8×(100-1),
=7.8×100,
=780;
(3)7×(
+
)×11,
=7××11×
+7×11×
,
=44+70,
=114;
(4)
÷[
×(
-
)],
=
÷[
×
],
=
÷
,
=4.
分析:(1)先算减法,再算乘法;
(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)先算减法,再算乘法,最后算除法.
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.
(1)(12.5-7.6)×(3-2.8),
=4.9×0.2,
=0.98;
(2)7.8×101-7.8,
=7.8×(100-1),
=7.8×100,
=780;
(3)7×(


=7××11×


=44+70,
=114;
(4)




=



=


=4.
分析:(1)先算减法,再算乘法;
(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)先算减法,再算乘法,最后算除法.
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.

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