The expression is .

Place value chart for 121 and 56.

Line up the decimal points and draw a line below the numbers.

 Annex one zero to align the numbers.

First find the difference on the ones digit.

Notice that it is not possible to subtract 1 from 6.

 So, 1 unit must be borrowed from tens column.

The difference of the ones digit = 11 – 6 = 5.

Next find difference of the tens digit.

Notice that it is not possible to subtract 5 from 1.

So, 1 unit must be borrowed from hundreds column.

The difference of the ones digit = 11 – 5 = 6.

The difference is 65.