一道数学题、 551+552+553+554+555+556+557=( ) * ( ) = ( )

问题描述:

一道数学题、 551+552+553+554+555+556+557=( ) * ( ) = ( )

551+557=2*554 552+556=2*554 553+555=2*554 原式=554*7=3878

=(554-3)+(554+3)+(554-2)+(554+2)+(554-1)+(554+1)+554
=554*7
=3878

=7*554=3878