20
10
The LCD of 7 and 20 is 140
The LCD of 7/10 and 18/25 is 50.
LCD(7, 5, 10) = 10
If that's 5/12, 10/13 and 7/9, the LCD is 468.
7/20 + 9/10 = 7/20 + 18/20 = 25/20 = 5/4
7 over 10
7/10 ÷ 2 = 7/20
140
140
7/10 = 14/20 14/20 + 11/20 = 25/20 = 5/4