Kani Math
Cosmic Abacus
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Mental math speed test

Twelve problems, one clock, one score. A benchmark you can repeat weekly to see whether practice is actually moving anything.

  • 4 rows × 2 digits, add & subtract
  • 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
    68
    + 93
    + 14
    + 68
    ?
  2. 2
    62
    + 72
    − 56
    − 18
    ?
  3. 3
    51
    + 67
    + 37
    + 49
    ?
  4. 4
    82
    + 55
    − 52
    − 10
    ?
  5. 5
    48
    + 11
    − 40
    + 77
    ?
  6. 6
    32
    + 20
    + 54
    + 75
    ?
  7. 7
    73
    − 44
    − 22
    + 26
    ?
  8. 8
    25
    − 13
    + 72
    − 23
    ?
  9. 9
    63
    − 62
    + 54
    + 58
    ?
  10. 10
    58
    − 54
    + 52
    + 27
    ?
  11. 11
    94
    + 84
    + 90
    + 25
    ?
  12. 12
    89
    + 60
    − 47
    + 65
    ?
Full answer key
  1. 68 + 93 + 14 + 68 = 243
  2. 62 + 72 − 56 − 18 = 60
  3. 51 + 67 + 37 + 49 = 204
  4. 82 + 55 − 52 − 10 = 75
  5. 48 + 11 − 40 + 77 = 96
  6. 32 + 20 + 54 + 75 = 181
  7. 73 − 44 − 22 + 26 = 33
  8. 25 − 13 + 72 − 23 = 61
  9. 63 − 62 + 54 + 58 = 113
  10. 58 − 54 + 52 + 27 = 83
  11. 94 + 84 + 90 + 25 = 293
  12. 89 + 60 − 47 + 65 = 167

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.

It also delivers the numbers for you — flashed on screen or read aloud, with the speed, digit count and number of rows under your control. That is the one thing a printed page cannot do.

  • ✓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.

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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

Practice without measurement drifts. A learner can put in twenty minutes a day for months and have no idea whether they are getting faster, because subjective effort feels identical at every level. A fixed test — same length, same difficulty, same format — turns that into a number.

Treat the score as a trend line, not a grade. Single results bounce around by ten or fifteen percent for reasons that have nothing to do with skill: sleep, time of day, whether the previous problem went badly. Four weeks of readings tell you something; one does not.

How to practise it

  1. 1Run it at the same time of day each week, on the same device.
  2. 2Do not warm up on the test itself — warm up on a different drill.
  3. 3Record both the score and the time; either alone is misleading.
  4. 4Change one variable at a time if you want to know what helped.

Questions

What is a good score?
There is no universal benchmark worth quoting — problem width, row count and answer format all change the number. Compare yourself to your own previous result, not to a table.
Should I prioritise speed or accuracy?
Accuracy, always. Speed built on a 70% accuracy base collapses the moment problems get harder; speed built on 100% keeps scaling.
How often should we test?
Weekly at most. Testing more often measures noise, and it eats practice time that would actually move the number.
Does this work as a placement test?
Not really — it measures speed at one fixed difficulty. The placement exam adapts its difficulty and is the right tool for finding a starting level.
Learn the techniqueMental abacus (anzan)Walk through it on the beads →