原式=347*69+653*(100-69)+306*19
=347*69+653*100-653*69+306*19
=653*100-69*(653-347)+306*19
=653*100-306*(69-19)
=653*100-153*100
=100(653-153)
=50000
原式=347*69+653*(100-69)+306*19
=347*69+653*100-653*69+306*19
=653*100-69*(653-347)+306*19
=653*100-306*(69-19)
=653*100-153*100
=100(653-153)
=50000