题目内容
计算: (1)﹣2+3﹣(﹣4)+(﹣1);
(2)
;
(3)
;
(4)
.
(2)
(3)
(4)
解:(1)﹣2+3﹣(﹣4)+(﹣1),
=(﹣2)+(+3)+(+4)+(﹣1),
=[(﹣2)+(+3)]+[(+4)+(﹣1)],
=1+3,
=4;
(2)
,
=
,
=6﹣1﹣
,
=4.3;
(3)
,
=
,
=﹣1;
(4)
,
=
,
=﹣4+1﹣4,
=﹣7.
=(﹣2)+(+3)+(+4)+(﹣1),
=[(﹣2)+(+3)]+[(+4)+(﹣1)],
=1+3,
=4;
(2)
=
=6﹣1﹣
=4.3;
(3)
=
=﹣1;
(4)
=
=﹣4+1﹣4,
=﹣7.
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