早教吧 育儿知识 作业答案 考试题库 百科 知识分享

计算:(1)(-3.5)+(+2.8)(2)(-27)+(-213)(3)(-534)+725(4)(-356)+(+356)

题目详情
计算:
(1)(-3.5)+(+2.8)
(2)(-
2
7
)+(-2
1
3

(3)(-5
3
4
)+7
2
5

(4)(-3
5
6
)+(+3
5
6
▼优质解答
答案和解析
(1)(-3.5)+(+2.8)
=-3.5+2.8
=-(3.5-2.8)
=-0.7.

(2)(−
2
7
)+(−2
1
3
)=−(
2
7
+2
1
3
)=−2
13
21


(3)(−5
3
4
)+7
2
5
=+(7
2
5
−5
3
4
)=1
13
20


(4)(−3
5
6
)+(+3
5
6
)=0.