15 11/20 + 12 1/10 + 2 7/20
⚠ 15 11/20 is read as the mixed number 15 + 11/20
⚠ 12 1/10 is read as the mixed number 12 + 1/10
Let's calculate: 15 + 1120 + 12 + 110 + 2 + 720
ℹ15 + 12 = 27‖1120 + 110 = 11 + 220
27 + 11 + 220 + 2 + 720
ℹ11 + 2 = 13‖27 + 2 = 29
29 + 1320 + 720
ℹ1320 + 720 = 13 + 720
29 + 13 + 720
ℹ13 + 7 = 20
29 + 2020
ℹ2020 = 1
29 + 1
▶Result:   30