15*34-15*14+10*25-15*10+10*75
15*34-15*14+10*25-15*10+10*75=15*(34-14)+10*(25-15+75)=15*20+10*85=300+850 =1150
= 15 * ( 34 - 14) + 10 * ( 25 - 15) +10 * 75 = 15 * 20 + 10 * 10 + 10 * 75 = 15 * 2 * 10 + 10 * 10 + 10 * 75 = 10 * ( 15 * 2 + 10 + 75 ) = = 10 * ( 30 + 10 + 75) = 10 * 115 = 1150