{(2/15加3/49）乘15减1]乘4.9简便运算
问题描述：
{(2/15加3/49）乘15减1]乘4.9简便运算
答
{(2/15加3/49）乘15减1]乘4.9
=(2+3/49*15-1)*4.9
=(1+3/49*15)*4.9
=1*4.9+3/49*15*4.9
=4.9+3*15*0.1
=4.9+4.5
=9.4