计算 (1)48÷3-21/2×12+24. (2)(3+25)2-(4+7)(4-7)

问题描述:

计算  
(1)

48
÷
3
-2
1
2
×
12
+
24
.     
(2)(3+2
5
2-(4+
7
)(4-
7

(1)原式=

48÷3
-2
1
2
×12
+2
6

=4-2
6
+2
6

=4;
(2)原式=9+12
5
+20-(16-7)
=29+12
5
-9
=20+12
5