4.7*2.8+2.5*2.8+7.2*7.2=?用简便方法计算
问题描述:
4.7*2.8+2.5*2.8+7.2*7.2=?用简便方法计算
答
4.7*2.8+2.5*2.8+7.2*7.2
=(4.7+2.5)*2.8+7.2*7.2
=7.2*2.8+7.2*7.2
=(2.8+7.2)*7.2
=10*7.2
=72