(1000+123+234)×(123+234+345)-(1000+123+234+345)×(123+234)

问题描述:

(1000+123+234)×(123+234+345)-(1000+123+234+345)×(123+234)
简便运算

(1000+123+234)×(123+234+345)-(1000+123+234+345)×(123+234)
=1000(123+234+345)+(123+234)(123+234+345)-1000(123+234)-(123+234+345)(123+234)
=1000(123+234+345)-1000(123+234)
=1000*345
=345000