💡
Small Friends
are pairs that add up to 5. When you can't add or subtract directly on the abacus, use the 5's
complement formula. Remember: small friend of 1 is 4, of 2 is 3, of 3 is 2, of 4 is 1.
➕ Addition Formulas
+1 = +5 − 4
Small friend of 1 is 4
+2 = +5 − 3
Small friend of 2 is 3
+3 = +5 − 2
Small friend of 3 is 2
+4 = +5 − 1
Small friend of 4 is 1
➖ Subtraction Formulas
−1 = −5 + 4
Small friend of 1 is 4
−2 = −5 + 3
Small friend of 2 is 3
−3 = −5 + 2
Small friend of 3 is 2
−4 = −5 + 1
Small friend of 4 is 1
🆕 Abacus Bead Diagrams
Each rod shows beads: the top bead (heaven bead = 5) and four lower beads (earth beads = 1 each).
Active beads are shown in pink/red.
✎ Practice Problems
Use the 5's complement formula on your abacus to solve each problem: