Question

Вычесли удобным способом. 87*64+87*36 39*16+39*4 96*77-96*76 48*61-40*61 24*49+24 34*21-34

Answer 1

87*64=5568  87*36=3132  5568+3132=8700
39*16=624  39*4=156  624+156=780
96*77=7392  96*76=7296   7392-7296=96
48*61=2928   40*61=2440   2928-2440=488
24*49=1176   1176+24=1200
34*21=714   714-34=680

Answer 2

87*64+87*36=87*(64+36)=87*100=8700
39*16+39*4=39*(16+4)=39*20=780
96*77-96*76=96*(77-76)=96*1=96
48*61-40*61=61*(48-40)=61*8=488
24*49+24=24*(49+1)=24*50=1200
34*21-34=34*(21-1)=34*20=680