1. Add directly when you can
To calculate 2 + 3, first move two earth beads to the beam. Three more earth beads are not available, so this example leads naturally to the next technique. For 2 + 2, simply move two more earth beads up and read 4.
01
Set 2
02
Move 2 more beads
03
Read 4
2. Use friends of 5
If earth beads run out, exchange with the heaven bead. To add 3 to 2, add 5 by moving the heaven bead down, then remove 2 earth beads. This works because 3 = 5 − 2.
1 + 4 = 5
2 + 3 = 5
3. Use friends of 10 to carry
When a rod cannot hold the addition, add 1 on the rod to the left and subtract the complement on the current rod. For 8 + 7, add 10 and subtract 3: carry 1 ten, then change 8 to 5. The answer is 15.
1 ↔ 9
2 ↔ 8
3 ↔ 7
4 ↔ 6
5 ↔ 5
Say the move aloud while learning: “plus 7 is plus 10, minus 3.” The words help the bead pattern become automatic.