748-351+252-149简便法运算

问题描述:

748-351+252-149简便法运算

748-351+252-149
=(748+252)-(351+149)
=1000-500
=500

(750+250-350-150)+(2-1+2+1)=504

(750-2+250+2)-(350+1+150-1)
=1000-500
=500

748+252-(351+149)=1000-500=500

=748+252-351-149
=1000-(351+149)
=1000-500
=500