1) 3 3/4 * 1 1/5 = 15/4 * 6/5 = 9/2=4,5
2) 2,55+2,7=5,25= 5 1/4=21/4
3) 0,1 - 1/80 = 1/10 - 1/80 = 8/80 - 1/80 = 7/80
4) 21/4 : 7/80 = 21/4 * 80/7 = 60
5)4,5 + 60=64,5
ответ: 64,5
1. 4(2)
2. 15(2)
3. 7(1)
4. 7(4)
5. 13(1)
6. 5(1)
7. 4(2)
8. 13(1)
9. 7(2)
(19-7b)+(9b-8)=(19-7*1)+(9*2-8)=(19-7)+(18-8)=12+10=22