Question

Вычислите удобным способом используя распределительный закон умножения 71*9 39*9 15*61 5*52 3*901 701*12

Answer 1

71*9 = (70+1)*9 = 70*9+1*9 = 7*9*10+1*9 = 63*10+9 = 630+9 = 639

39*9 = (30+9)*9 = 30*9+9*9 = 3*9*10+9*9 = 27*10+81 = 270+81 = 351

15*61 = 15*(60+1) = 15*60+15*1 = 15*6*10+15*1 = 90*10+15 = 900+15 = 915

5*52 = 5*(50+2) = 5*50+5*2 = 5*5*10+5*2 = 25*10+10 = 250+10 = 260

3*901 = 3*(900+1) = 3*900+3*1 = 3*9*100+3*1 = 27*100+3 = 2700+3 = 2703

701*12 = (700+1)*12 = 700*12+1*12 = 7*12*100+1*12 = 84*100+12 = 8400+12 = 8412