Hi Hamza,

You are not carrying over 1 across.

5459 x 11 =

First digit 5 becomes the first digit of the answer so

5459 x 11 = 5 _ _ _ _

Adding the first two digits we get 5 + 4 = 9

5459 x 11 = 5 9 _ _ _

Adding the next two digits we get 4 + 5 = 9

5459 x 11 = 5 9 9 _ _

Adding the next two digits we get 5 + 9 = 14

Since 14 has two digits we need to carry over the 1 so 599 becomes 600

5459 x 11 = 6 0 0 4 _

This is where you are making the mistake. You are not carrying the number across. You are adding it only to 9. Another way to think about it is when you add 1 to 9 you get 10 which is also a two digit number, so you have to carry over the number again to the next 9. This will also result in two digit number so you carry over the 1 to the next 5 to make it 6.

Finally 9 becomes the last digit of the answer.

5459 x 11 = 6 0 0 4 9

Let me know if this clarifies.