计算:(1)(-20)+(+3)-(-5)-(-7);(2) (- 3 4 - 7 9 + 5 12 )×(

2025-06-29 13:23:15
推荐回答(1个)
回答1:

(1)原式=-20+3+5+7
=-5;

(2)原式=(-
3
4
)×(-36)-
7
9
×(-36)+
5
12
×(-36)
=27+28-15
=40;

(3)原式=-4×(-5)-6÷4×
1
4

=20-
3
2
×
1
4

=20-
3
8

=19
5
8