147×85 + 53×60 + 147×15 +53×40 =
= 147×(85+15) + 53×(60+40)=
= 147×100 +53×100=
= 100×(147+53) =100×200=
= 20000
275×32+ 725×28 + 275×19 +725× 22=
= 275× (32+19) + 725×(28+22)=
= 275 × 51 + 725 ×50 =
= 275× 50 + 275×1 +725×50=
= 50×(275+725) + 275 =
= 50×1000 + 275 =
= 50000 +275=50275
326 × 67 + 174× 29 + 326× 33 + 174× 71 =
= 326× (67+33) + 174×(29+71)=
= 326×100 + 174×100=
= 100×( 326+174) =
= 100×500 = 50000