2/5 - 3/10 = (2×2)/(5×2) - 3/10 = 4/10 - 3/10 = (4-3)/10 = 1/10.
2/5 + 3/10 = 4/10 + 3/10 = 7/10
1/5 + 3/10 = 2/10 + 3/10 = 5/10 = 1/2
10/15 2/3 = 10/15 10/15 = 3/5
2 3/10
3/5 + 9/10 = 6/10 + 9/10 = 15/10 = 3/2 or 11/2
9/10 + 3/5 = 9/10 + 6/10 = 15/10 = 3/2 or 11/2
3/2 - 7/10 = 15/10 - 7/10 = 8/10 = 4/5
3/10
(7-3)/10 = 4/10 = 2/5
3 over five 2/3 = 10/15, and 3/5 = 9/15. 2 over 3 (10/15) is obviously bigger than 3 over 5 (9/15).
No ------------------------------------------------ 4/5 = (4×2)/(5×2) = 8/10 8 ≠ 3 → 8/10 ≠ 3/10 → 4/5 ≠ 3/10