Kani Math
Cosmic Abacus
Launch App →
1️⃣

One-digit addition drills

Five single digits per column. Short enough for a five-year-old, long enough that memorised answers stop working.

  • 5 rows × 1 digits, addition
  • About 5 min
  • Free, no account

Sample problems

Real problems from this drill, with answers. Nothing to install, no account, no email — work them on paper, on a physical abacus, or in your head.

  1. 1
    3
    + 7
    + 9
    + 7
    + 9
    ?
  2. 2
    4
    + 6
    + 7
    + 9
    + 5
    ?
  3. 3
    1
    + 8
    + 4
    + 5
    + 7
    ?
  4. 4
    5
    + 7
    + 6
    + 4
    + 2
    ?
  5. 5
    2
    + 5
    + 8
    + 2
    + 7
    ?
  6. 6
    4
    + 2
    + 3
    + 9
    + 3
    ?
  7. 7
    2
    + 5
    + 6
    + 5
    + 8
    ?
  8. 8
    9
    + 6
    + 7
    + 3
    + 9
    ?
  9. 9
    1
    + 6
    + 4
    + 2
    + 1
    ?
  10. 10
    3
    + 7
    + 3
    + 8
    + 4
    ?
Full answer key
  1. 3 + 7 + 9 + 7 + 9 = 35
  2. 4 + 6 + 7 + 9 + 5 = 31
  3. 1 + 8 + 4 + 5 + 7 = 25
  4. 5 + 7 + 6 + 4 + 2 = 24
  5. 2 + 5 + 8 + 2 + 7 = 24
  6. 4 + 2 + 3 + 9 + 3 = 21
  7. 2 + 5 + 6 + 5 + 8 = 26
  8. 9 + 6 + 7 + 3 + 9 = 34
  9. 1 + 6 + 4 + 2 + 1 = 14
  10. 3 + 7 + 3 + 8 + 4 = 25

This page is one drill. The app is the whole programme.

Kani Math is a full mental-arithmetic course, not a single exercise. Free to start, no signup, and it runs on the web, Android and iPhone.

  • ✓Nine levels, from the first bead to division
  • ✓Guided lessons that teach the technique, not just drills
  • ✓Flash, listening and abacus drills at a speed you set
  • ✓Versus matches against friends or the computer
  • ✓Say your answers out loud — the app listens and marks them
  • ✓Streaks, coins and badges, with parent and teacher views

Want to stay here? The demo further down runs right on this page.

Launch App →Try the demo ↓

Practise it now

The same drill, live in your browser, with a virtual soroban and instant marking.

1️⃣

Loads a full interactive drill right here on the page. It never asks who you are.

No signup. Nothing saved unless you ask.

Explore the free virtual abacus →How to use an abacus →Mental Math Drill →

About this drill

Single-digit addition is the drill everyone starts with and almost everyone under-practises. Two-term sums get memorised quickly — 6 + 7 becomes a fact, not a calculation — which feels like progress but trains nothing. Five terms in a column cannot be memorised, so the learner has to actually maintain a running total, and that is the skill that carries forward.

Every problem below is pure addition with no negative steps, and every running total stays small. That makes it usable with beads, with fingers, or entirely in the head, which is why it works equally well as a warm-up for an experienced learner and as a first exercise for a beginner.

How to practise it

  1. 1Read the full column once before starting.
  2. 2Add top to bottom at a steady pace, one number per beat.
  3. 3Do not say the running total out loud — hold it.
  4. 4Check the answer only after the last row.

Questions

Is this suitable for a complete beginner?
Yes. No carrying, no complements, no negative steps — the only requirement is recognising the digits 1 to 9.
Should my child use fingers?
For a short while it is fine, but it caps speed at roughly one number per second forever. Beads or a mental image both scale; fingers do not.
How many columns per session?
Ten to twenty is a good daily dose at this width. Short and daily beats long and weekly by a wide margin.
What comes next?
Two-digit addition, or the 5-complement rules if you want the abacus technique rather than more of the same arithmetic.
Learn the techniqueSmall friends (5-complements)Walk through it on the beads →