计算下面各题,能简便计算的要简便计算:
来源:学生作业帮 编辑:搜搜做题作业网作业帮 分类:数学作业 时间:2024/07/07 05:12:52
计算下面各题,能简便计算的要简便计算:
9 |
2 |
![计算下面各题,能简便计算的要简便计算:](/uploads/image/z/17234082-18-2.jpg?t=%E8%AE%A1%E7%AE%97%E4%B8%8B%E9%9D%A2%E5%90%84%E9%A2%98%EF%BC%8C%E8%83%BD%E7%AE%80%E4%BE%BF%E8%AE%A1%E7%AE%97%E7%9A%84%E8%A6%81%E7%AE%80%E4%BE%BF%E8%AE%A1%E7%AE%97%EF%BC%9A)
(1)
9
2×
5
4÷
9
2×
5
4
=
9
2×
5
4×
2
9×
5
4
=(
9
2×
2
9)×(
5
4×
5
4)
=1×
25
16
=
25
16
(2)
4
7×15-
4
7
=
4
7×(15-1)
=
4
7×14
=8
(3)
10
21÷[
5
6×(1-
2
3)]
=
10
21÷[
5
6×
1
3]
=
10
21÷
5
18
=
10
21×
18
5
=
12
7
9
2×
5
4÷
9
2×
5
4
=
9
2×
5
4×
2
9×
5
4
=(
9
2×
2
9)×(
5
4×
5
4)
=1×
25
16
=
25
16
(2)
4
7×15-
4
7
=
4
7×(15-1)
=
4
7×14
=8
(3)
10
21÷[
5
6×(1-
2
3)]
=
10
21÷[
5
6×
1
3]
=
10
21÷
5
18
=
10
21×
18
5
=
12
7