# How to Count on an Abacus

The abacus is an ancient calculating tool. Simple rules for counting on an abacus are described here.

### You will need

• An abacus
• A flat surface

Step 1 Place the abacus on a flat surface Place the abacus on a flat surface with the upper section away from you. Push all the beads in the upper and lower sections away from the central crossbar.

Step 2 Move the beads to count Move the corresponding number of beads on the right-most lower deck column toward the central crossbeam to count from one to five.

Step 3 Carry over the beads as needed Set the 5-bead above the crossbeam in the same column when you have five beads in the lower section and need to add one more. Then clear the five beads in the lower section.

Step 4 Continue carrying over the beads Set a second 5-bead in the same column when you have five more beads set in the lower section and need to add one more. The two beads in the upper section correspond to the number 10. Clear the five beads in the lower section.

Step 5 Use columns to the left as needed Continue counting in the same manner using columns to the left to represent numbers of increasing value. From right to left, the first vertical column represents units, the next represent 10s, then 100s, and so on.