In this lesson, you will learn how to take away 1s and 2s on your soroban when there aren't any/enough 'one' beads left to complete your sums, but there is a 'heavan' or five bead left. To take away 1 (-1), take away 5 (-5) and add 4 'one' beads. -1 = -5 + 4. To take away 2 (-2), take away five (-5) and add 3 'one' beads. -2 = -5 + 3.