“（8分之1+24分之1+48分之1+80分之1+120分之1+168分之1）*56”用简便方法计算

(1/8+1/24+1/48+1/80+1/120+1/168)*56
=(1+1/3+1/6+1/10+1/15+1/21)*(1/8)*56
=(1+2/6+1/6+1/10+1/15+1/21)*7
=(1+1/2+1/10+1/15+1/21)*7
=(1+5/10+1/10+1/15+1/21)*7
=(1+6/10+1/15+1/21)*7
=(1+36/60+4/60+1/21)*7
=(1+4/6+1/21)*7
=7+28/6+1/3
=7+28/6+2/6
=7+5
=12