Kani Math
Cosmic Abacus
Launch App →
2️⃣

Two-digit addition drills

Two rods, five rows, and carries that have to happen the moment they occur — the width where abacus method starts beating pencil and paper.

  • 5 rows × 2 digits, addition
  • About 7 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
    89
    + 95
    + 11
    + 22
    + 62
    ?
  2. 2
    89
    + 82
    + 85
    + 16
    + 19
    ?
  3. 3
    33
    + 77
    + 73
    + 98
    + 37
    ?
  4. 4
    54
    + 42
    + 59
    + 12
    + 76
    ?
  5. 5
    46
    + 32
    + 56
    + 18
    + 51
    ?
  6. 6
    54
    + 28
    + 62
    + 17
    + 40
    ?
  7. 7
    33
    + 58
    + 27
    + 32
    + 25
    ?
  8. 8
    96
    + 12
    + 30
    + 60
    + 63
    ?
  9. 9
    55
    + 16
    + 54
    + 93
    + 62
    ?
  10. 10
    37
    + 80
    + 12
    + 95
    + 69
    ?
Full answer key
  1. 89 + 95 + 11 + 22 + 62 = 279
  2. 89 + 82 + 85 + 16 + 19 = 291
  3. 33 + 77 + 73 + 98 + 37 = 318
  4. 54 + 42 + 59 + 12 + 76 = 243
  5. 46 + 32 + 56 + 18 + 51 = 203
  6. 54 + 28 + 62 + 17 + 40 = 201
  7. 33 + 58 + 27 + 32 + 25 = 175
  8. 96 + 12 + 30 + 60 + 63 = 261
  9. 55 + 16 + 54 + 93 + 62 = 280
  10. 37 + 80 + 12 + 95 + 69 = 293

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.

2️⃣

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

Two-digit columns are the first width where the written algorithm and the abacus genuinely diverge. On paper you add all the units, write a carry, then add all the tens. On the abacus the carry happens the instant it is created, so there is never a pending digit anywhere — which is exactly why the procedure survives being moved into the head later.

The drills below hold every running total under 500, so two rods are always enough and no problem needs a third. That constraint keeps the exercise about the carry itself rather than about managing a wider workspace.

How to practise it

  1. 1Set the first number on the two rightmost rods.
  2. 2Add each row units-first, then tens — never the other way round.
  3. 3Resolve every carry immediately; do not defer it to the end.
  4. 4Read both rods together as one number when you finish.

Questions

Why units before tens?
Because a units carry changes the tens rod. Going the other way means revisiting a rod you already set, which is the habit that breaks mental work later.
Do I need a real abacus?
No. The interactive drill on this page runs a full virtual soroban in the browser, and every sample below is solvable with pencil and paper too.
Is this the same as "2 digit abacus practice"?
Yes — two-digit here means each number in the column has two digits, so the work happens across two rods.
My child is accurate but slow.
That is the correct order. Speed comes from removing hesitation, not from hurrying; keep accuracy at 100% and let the pace rise on its own.
Learn the techniqueBig friends (10-complements)Walk through it on the beads →