Set up the subtraction problem in long subtraction format.

Borrow from the digit in the next column to the left. Add the borrowed to . Reduce the number that was borrowed from by .

Subtract from .

Borrow from the digit in the next column to the left. Add the borrowed to . Reduce the number that was borrowed from by .

Subtract from .

Subtract from .

The result of is .

Evaluate 120-78