52*295+56*6-56
=52*295+56*(6-1)
=52*295+56*5
=52*295+(52+4)*5
=52*295+52*5+4*5
=52*(295+5)+20
=52*300+20
=15600+20
=15620
56*295+56*6-56
=56*(295+6-1)
=56*300
=16800