| 8.75-5.375+2.25+4.125 | ×〔( + )÷ 〕 | 45× + ×55 | 4.3-( +2.4÷ ) |
(1)8.75-5.375+2.25+4.125,
=(8.75+2.25)-(5.375-4.125),
=11-1.25,
=9.75;
(2)
×〔(
+
)÷
〕,=
×〔
÷
〕,=
×
,=
;(3)45×
+
×55,=(45+55)×
,=100×
,=35;
(4)4.3-(
+2.4÷
),=4.3-(
+0.9),=4.3-1.5,
=2.8.
分析:(1)根据加法交换律和结合律进行简算;
(2)先算加法,再算除法,最后算乘法;
(3)根据乘法分配律进行简算;
(4)先算除法,再算减法,最后算减法.
点评:根据题意,先弄清运算顺序,然后再进一步计算即可;能简算的要简算.