1/3 + 2/3 = 3/3 = 1
19 - 4/21 = 19 - 0.19047 = 18.80953
2/15 + 4/15 + 4/15 = 10/15 = 2/3
57/100 - 17/100 = 40/100 = 2/5
1/3 + 2/3 = 3/3 = 1
19 - 4/21 = 19 - 0.19047 = 18.80953
2/15 + 4/15 + 4/15 = 10/15 = 2/3
57/100 - 17/100 = 40/100 = 2/5