The simplest form of 105 over 441 is 5 over 21.
105 over one thousand as a fraction in simplest form = 21/200
55/105 = 11/21
21 over 200
21/2
105/441 = 5/21
60/105 = 12/21 = 4/7
7/21 OR 1/3
Divide them both by their GCF, 21. Get 2/5
21/80 is already in its simplest form
1050 / 1200 = 105 / 120 = 21 / 24 = 7 / 8
5/105 = 1/21