Question

56×7十45×7一7用简便方法计算

Answer 1

56×7+45×7-7
=7×(56+45-1)
=7*100
=700

Answer 2

56×7+45×7-7
=(56+45-1)×7
=10×7
=70

Answer 3

原式=7×(56+45-1)=7×100=700