Adding and taking away

Big numbers on the abacus

Same five moves, more rods. Work the digits from left to right and let each rod look after itself.

Updated 11 September 2026 · 2 min read

Same moves, more rods

Big numbers need nothing new. Set the first number, then take the second number's digits from left to right, each onto the rod of the same place. Every digit is one of the moves you already know: direct, the 5-bead, 5-and-a-bit, a little friend or a big friend.

Worked example: 23 + 45

The tens digit needs a little friend; the ones digit is a plain 5-bead move.

Worked example: 23 + 45 = 68

Move 1. Set 23. No room for 4. Put 5 on and take its friend 1 back off — one motion. ☝️ index finger

Move 2. Push the 5-bead down. ☝️ index finger

Answer: 68

Worked example: 38 + 27

This one carries: 8 + 7 is too much for one rod, so the big friend of 7 comes off and a 1 goes onto the tens rod.

Worked example: 38 + 27 = 65

Move 1. Set 38. No room for 2. Put 5 on and take its friend 3 back off — one motion. ☝️ index finger

Move 2. Too full to add 7 here. So take off its big friend, 3. Index finger down 3 beads. ☝️ index finger

Move 3. This rod first, then carry 1 to the left. Thumb up 1 bead. 👍 thumb

Answer: 65

Worked example: 52 − 17

A little friend on the tens rod, then a borrow for the ones — and the borrowed digit lands with a little friend of its own.

Worked example: 52 − 17 = 35

Move 1. Set 52. No little beads to take 1. Take 5 off and put its friend 4 back — one motion. 👍 thumb + ☝️ index finger, together

Move 2. Not enough here to take 7. Its big friend is 3. Taking away? Borrow from the LEFT rod first. Index finger down 1 bead. ☝️ index finger

Move 3. No room for 3. Put 5 on and take its friend 2 back off — one motion. ☝️ index finger

Answer: 35

Column drills

Abacus competitions often use columns: a list of numbers to add and take away one after another. The board holds the running total, so there is nothing to remember between lines.

A five-line column, with the board after each line
Line	Board shows
12	12
+ 34	46
− 5	41
+ 27	68
− 18	50

To check a column, run it backwards: take each number back off, from the bottom up. If you land on zero, it was right.

Ready to try it?

Practise two-digit sums →

Printable practice: Level 6 worksheet · Level 7 worksheet

Common questions

Why do you work left to right on an abacus?

It matches how you read and hear numbers, so you can start before the whole number is said. A carry only ever touches a rod you have just finished.

What happens if a carry lands on a 9?

That rod overflows too, so you repeat the big-friend move there and carry again, one rod further left. 99 + 1 carries twice.