七年级简便计算 要过程和结果
来源:学生作业帮 编辑:拍题作业网作业帮 分类:数学作业 时间:2024/04/29 05:46:43
七年级简便计算 要过程和结果
1.(+15)+(-20)+(+28)+(-10)+(-5)+(-7)
2.(+2又3/4)+(-1又5/8)+(-5/6)+1/2
3.(-3又1/2)+(-2又1/9)+3.5+(-8/9)+1/2
4.(-1)+(+2)+(-3)+(+4)+.+(-41)+(+42)
1.(+15)+(-20)+(+28)+(-10)+(-5)+(-7)
2.(+2又3/4)+(-1又5/8)+(-5/6)+1/2
3.(-3又1/2)+(-2又1/9)+3.5+(-8/9)+1/2
4.(-1)+(+2)+(-3)+(+4)+.+(-41)+(+42)
(+15)+(-20)+(+28)+(-10)+(-5)+(-7)
=15-20+28-10-5-7
=43-42
=1
2.(+2又3/4)+(-1又5/8)+(-5/6)+1/2
=3-(39/24+20/24)
=3-59/24
=13/24
3.(-3又1/2)+(-2又1/9)+3.5+(-8/9)+1/2
=[(-3又1/2)+1/2]-(2又1/9+8/9)+3.5
=-3-3+3.5
=-2.5
4.(-1)+(+2)+(-3)+(+4)+.+(-41)+(+42)
=1*21
=21
=15-20+28-10-5-7
=43-42
=1
2.(+2又3/4)+(-1又5/8)+(-5/6)+1/2
=3-(39/24+20/24)
=3-59/24
=13/24
3.(-3又1/2)+(-2又1/9)+3.5+(-8/9)+1/2
=[(-3又1/2)+1/2]-(2又1/9+8/9)+3.5
=-3-3+3.5
=-2.5
4.(-1)+(+2)+(-3)+(+4)+.+(-41)+(+42)
=1*21
=21