1287*1/2*3/40+3/4*870*1/4+3/4

问题描述:

1287*1/2*3/40+3/4*870*1/4+3/4
1287又1/2*3/40+3/4*870又1/4+3/4

(1287+1/2)*3/40+3/4*(870+1/4)+3/4
=(1287+1/2)*3/40+3/4*(870+1/4+1)
=(1287+1/2)*3/40+3/40*(871+1/4)*10
=(1287+1/2)*3/40+3/40*(8710+10/4)
=3/40*(1287+1/2+8710+10/4)
=3/40*(1287+2/4+8710+10/4)
=3/40*(1287+12/4+8710)
=3/40*10000=3*250=750