计算下面各题,注意使用简便算法.73×57÷13; 420×(37+56); 425×99+425;[4-(34-38)]×429.
(1)
×
÷
=
×
×3
=5
(2)420×(
+
)
=420×
+420×
=180+350
=530
(3)
×99+
=
×(99+1)
=
×100
=16
(4)[4-(
-
)]×
=[4-
]×
=
×
=
.
7 |
3 |
5 |
7 |
1 |
3 |
=
7 |
3 |
5 |
7 |
=5
(2)420×(
3 |
7 |
5 |
6 |
=420×
3 |
7 |
5 |
6 |
=180+350
=530
(3)
4 |
25 |
4 |
25 |
=
4 |
25 |
=
4 |
25 |
=16
(4)[4-(
3 |
4 |
3 |
8 |
4 |
29 |
=[4-
3 |
8 |
4 |
29 |
=
29 |
8 |
4 |
29 |
=
1 |
2 |
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