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脱式计算下列各题,能简算的要简算.(1)2220÷37-23(2)7.2×4.5+2.8(3)516×30+516×2(4)29÷[56×(45-23)](5)17.2-4x=5.2(解方程)

题目详情
脱式计算下列各题,能简算的要简算.
(1)2220÷37-23          
(2)7.2×4.5+2.8
(3)
5
16
×30+
5
16
×2  
(4)
2
9
÷[
5
6
×(
4
5
-
2
3
)]
(5)17.2-4x=5.2 (解方程)
▼优质解答
答案和解析
(1)2220÷37-23
=60-23
=37;
          
(2)7.2×4.5+2.8
=32.4+2.8
=35.2;

(3)
5
16
×30+
5
16
×2  
=
5
16
×(30+2)
=
5
16
×32
=10;
  
(4)
2
9
÷[
5
6
×(
4
5
-
2
3
)]
=
2
9
÷[
5
6
×
2
15
]
=
2
9
×9
=2;

(5)17.2-4x=5.2 
17.2-4x+4x-5.2=5.2+4x-5.2 
            4x=12
         4x÷4=12÷4
             x=3.