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用简便方法计算.427-156-441230-299137+149+163456+197.

题目详情
用简便方法计算.
427-156-44    
1230-299    
137+149+163     
456+197.
▼优质解答
答案和解析
(1)427-156-44
=427-(156+44)
=427-200
=227;

(2)1230-299
=1230-(300-1)
=1230-300+1
=930+1
=931;

(3)137+149+163
=137+163+149
=300+149
=449;

(4)456+197
=456+(200-3)
=456+200-3
=656-3
=653.