a)(b:5x501-1):1000=251
(b:2505-1):1000=251
(b:2505-1)=251x1000
b:2505-1=251000
b:2505=251001
b=251001:2505
b=100.2
4160:65+1938=670
64+c-1938=670
64+c=670+1938
64+c=2608
c=2608-64
c=2544
c)(1040:8+10870):11+2000-b=465
(130+10870):11+2000-b=465
11000:11+2000-b=465
1000+2000-b=465
3000-b=465
b=3000-465
b=2535