题目内容
计算:
(1)|-
|+
÷(
+|-
|);
(2)(-3)+(-7)-(+8)-(-5);
(3)3
-8
-(-2
);
(4)(
+0.5-
)-(
-
-
).
(1)|-
1 |
2 |
1 |
2 |
2 |
9 |
2 |
3 |
(2)(-3)+(-7)-(+8)-(-5);
(3)3
5 |
6 |
3 |
4 |
1 |
6 |
(4)(
1 |
3 |
5 |
6 |
1 |
2 |
5 |
6 |
1 |
3 |
分析:(1)首先化简绝对值,再按运算顺序计算;
(2)先化简,去掉括号,再分类计算;
(3)化简最后一个的减数,把同分母分数先运算,再进一步计算;
(4)去掉括号,先计算同分母分数,再进一步计算.
(2)先化简,去掉括号,再分类计算;
(3)化简最后一个的减数,把同分母分数先运算,再进一步计算;
(4)去掉括号,先计算同分母分数,再进一步计算.
解答:解:(1)原式=
+
÷(
+
)
=
+
×
=
+
=
;
(2)原式=-3-7-8+5
=-18+5
=-13;
(3)原式=3
-8
+2
=6-8
=-2
;
(4)原式=
+
-
-
+
+
=
.
1 |
2 |
1 |
2 |
2 |
9 |
2 |
3 |
=
1 |
2 |
1 |
2 |
9 |
8 |
=
1 |
2 |
9 |
16 |
=
17 |
16 |
(2)原式=-3-7-8+5
=-18+5
=-13;
(3)原式=3
5 |
6 |
3 |
4 |
1 |
6 |
=6-8
3 |
4 |
=-2
3 |
4 |
(4)原式=
1 |
3 |
1 |
2 |
5 |
6 |
1 |
2 |
5 |
6 |
1 |
3 |
=
2 |
3 |
点评:此题考查有理数的混合运算,注意在运算过程中,抓住同分母分数、互为相反数等相加的数字先计算,使计算简便.
练习册系列答案
相关题目