Subtracting Whole Numbers

To subtract, stack the numbers with columns aligned and work from the right. If a column's top digit is too small, borrow ten from the column to its left.

Worked example. $1\,604 - 358$:

Units: $4 - 8$ won't go, so borrow. The tens digit is $0$, so borrow from the hundreds first. After borrowing: units $14 - 8 = 6$, tens $9 - 5 = 4$, hundreds $5 - 3 = 2$, thousands $1$. Answer $1\,246$.