1) 28/67*(10 11/13-2 11/13:1/2):3 1/2=8/13
2 11/13:1/2=37/13*2/1=74/13
10 11/13-74/13=141/13-74/13=67/13
28/67*67/13=28/13
28/13:3 1/2=28/13:7/2=28/13*2/7=8/13
38/4=9(ост.2)
(4·9+2=36+2=38)
24=2*2*2*3
42=2*3*7
НОД(24,42)=2*3=6
24=2*2*2*3
4=2*2 Общие делители: 4,2