56*7+45*7-7=(56+45-1)*7=100*7=700
56*7+45*7-7=7*(56+45-1)=7*100=700
用简便方法计算:56*7加上45*7减七=7*(56+45-1)=7*100=700,
56*7+45*7-7=(56+45)*7-7=700-7=693
56十45一1再乘以七等于700
=(56+45)*7=101*7=707
56x7x45x7一7 =7x(56+45-1) =7x100 =700
57*7+45*7-7=(57+45-1)*7=(100+1)*7=100*7+7=707 供参考
原式=7*(56+43+1)=7*100=700.
原式=56x7+56x5-56x2=56x(7+5-2)=56x10=560供参考.