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简便计算(1)453+209+547+291(2)5356-(1356+489)(3)1439-(439-187)(4)9+99+999+9999+99999(5)675-238+1325-262(6)200-199+198-197+196-195+…+4-3+2-1.

题目详情
简便计算
(1)453+209+547+291                      
(2)5356-(1356+489)
(3)1439-(439-187)
(4)9+99+999+9999+99999
(5)675-238+1325-262       
(6)200-199+198-197+196-195+…+4-3+2-1.
简便计算
(1)453+209+547+291                      
(2)5356-(1356+489)
(3)1439-(439-187)
(4)9+99+999+9999+99999
(5)675-238+1325-262       
(6)200-199+198-197+196-195+…+4-3+2-1.






▼优质解答
答案和解析
(1)453+209+547+291                      
=(453+547)+(209+291)
=1000+500
=1500

(2)5356-(1356+489)
=5356-1356-489
=4000-489
=3511            

(3)1439-(439-187)
=1439-439+187
=1000+187
=1187

(4)9+99+999+9999+99999
=10-1+100-1+1000-1+10000-1
=11110-4
=11106

(5)675-238+1325-262       
=(675+1325)-(238+262)
=2000-500
=1500

(6)200-199+198-197+196-195+…+4-3+2-1
=(200-199)+(198-197)+(196-195)+…+(4-3)+(2-1)
=1+1+1+…+1+1
=100