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
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
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