B+60,19-(68,7-9,1),еслиb=21,021.
21,021+60,19-(68,7-9,1)= 1) 68,7-9,1=59,6 2) 21,021+60,19=81,211 3) 81,211-59,6=21,611
21,021+60,19-(68,7-9,1)=81,211-59,6=-21,611
21,611*