考点:整数四则混合运算,运算定律与简便运算
专题:运算顺序及法则
分析:(1)把495看作500-5,然后再根据减法的性质进行简算;
(2)把397看作400-3,然后再根据加法交换律进行简算;
(3)根据加法交换律和结合律进行简算;
(4)根据减法的性质进行简算;
(5)根据减法的性质进行简算;
(6)先算小括号里面的加法,再算括号外面的加法;
(7)先算乘法,再算减法;
(8)按照从左向右的顺序进行计算.
解答:
解:(1)563-495
=563-(500-5)
=560-500+3
=60+3
=63;
(2)397+656
=(400-3)+656
=400+656-3
=1056-3
=1053;
(3)391+568+709+32
=(391+709)+(568+32)
=1100+600
=1700;
(4)1937-672-937
=1937-937-672
=1000-672
=328;
(5)1249-(673+249)
=1249-673-249
=1249-249-673
=1000-673
=327;
(6)7589+(3565+231)
=7589+3887
=11385;
(7)1236-185×6
=1236-1110
=126;
(8)482-188+118
=294+118
=412.
点评:考查了运算定律与简便运算,四则混合运算.注意运算顺序和运算法则,灵活运用所学的运算定律简便计算.