Hi

From ii

11 ? 8 = 8 ? 11

From iii

8 ? 11 = 8 ? (8 + 3) = (8 ? 3) 11 / 3

Now we need to find 8 ? 3

From ii

8 ? 3 = 3 ? 8

From iii

3 ? 8 = 3 ? (3 + 5) = (3 ? 5) 8 / 5

Now we need to find 8 ? 3

From iii

3 ? 5 = 3 ? (3 + 2) = (3 ? 2) 5 / 2

Now we need to find 3 ? 2

From ii

3 ? 2 = 2 ? 3

2 ? 3 = 2 ? (2 + 1) = (2 ? 1) 3 / 1

Now we need to find 2 ? 1

From ii

2 ? 1 = 1 ? 2

1 ? 2 = 1 ? (1 + 1) = (1 ? 1) 2 / 1

From i

1 ? 1 = 1 + 2 = 3

Therefore you can go up the chain to get 11 ? 8