计算.(1)(+7.8)+(-6)+(-945);(2)(+4)+(-312)+(-78)+(+3.5)+(-318);(3)(-218)+(-312)+(+5)+(+1.125)+(+412).-数

题目简介

计算.(1)(+7.8)+(-6)+(-945);(2)(+4)+(-312)+(-78)+(+3.5)+(-318);(3)(-218)+(-312)+(+5)+(+1.125)+(+412).-数

题目详情

计算.
(1)(+7.8)+(-6)+(-9
4
5
)
;      
(2)(+4)+(-3
1
2
)+(-
7
8
)+(+3.5)+(-3
1
8
)

(3)(-2
1
8
)+(-3
1
2
)+(+5)+(+1.125)+(+4
1
2
)
题型:解答题难度:中档来源:不详

答案

(1)原式=[(+7.8)-9class="stub"4
5
]+(-6)
=(7.8-9.8)-6
=-2-6
=-8;

(2)原式=(+4)+[-3class="stub"1
2
+(+3.5)]+[(-class="stub"7
8
)+(-3class="stub"1
8
)]
=4-4
=0;

(3)原式=[-2class="stub"1
8
+(+1.25)]+[(-3class="stub"1
2
)+(+4class="stub"1
2
)]+(+5)
=-1+1+5
=5.

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