arithmetic
Mental arithmetic trainer. Every drill is a pattern. Every answer is timed. Every run is kept in the history.
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Reference
Patterns
A pattern generates random questions without end. Several parts separated by commas: each question comes from one part, chosen at random.
| pattern | meaning | example | answer |
|---|---|---|---|
| 75x2d | 75 × any 2-digit number | 75 × 48 | 3,600 |
| 2dx2d | 2-digit × 2-digit | 37 × 82 | 3,034 |
| 75x2..4d | 75 × a 2-, 3- or 4-digit number | 75 × 2270 | 170,250 |
| 10..99x7 | range, both ends included | 63 × 7 | 441 |
| 3d^2, 2d^3 | square, cube | 417² | 173,889 |
| 4d/1d | division with remainder | 8231 ÷ 6 | 1371 r5 |
| 3d+3d, 3d-3d | add, subtract (bigger first; never negative) | 812 − 345 | 467 |
| 75x2d,25x2d | mix of parts | either | — |
Operands
- N
- fixed number. Two fixed operands (7x8) is invalid.
- kd
- any k-digit number. 1d = 2..9.
- a..bd
- a number with a to b digits.
- a..b
- integer from a to b, inclusive.
Normalization
Lowercase; spaces removed; * and × → x; ÷ → /; ² ³ → ^2 ^3; 2-4d → 2..4d (5-2d stays a subtraction).
Answers
3,600 = 3.600 = 3 600 = 3600. Division: 1371 r5 = 1371 rem 5; remainder 0: quotient only. Words: accents and case ignored.
Modes
| input | mode | ends when | record |
|---|---|---|---|
| 75x2d | practice | q | — |
| 75x2d 20 | benchmark | 20 answers | fastest total; perfect runs only |
| 75x2d s | sprint | 60 s; a late answer isn't counted | most correct |
During a run: s skips (counts as wrong); q or Esc stops. Per answer: ✓ time and streak, or ✗ and the right answer. At the end: right/done, total time, seconds per question and the new best, if any.
Commands
- N, N 20, N s
- runs saved drill N in each mode.
- h
- last 30 runs, grouped by day.
- h N
- drill N's runs, with up to 3 misses each.
- mix N M
- mixes drills N and M into a new drill.
- del N
- removes drill N from the list. Its history is kept.
- major
- peg table, gaps and major.txt editor.
- seq
- saved sequences, with their words.
- export
- downloads quickmath.json: drills, history, pegs and sequences.
- ?
- this reference.
Every drill you run is saved to the list. Per row: accuracy (green ≥ 90%, yellow ≥ 70%, red < 70%), average seconds per correct answer, runs, ⚡ best sprint, ⏱N:T best perfect N-question benchmark.
Data
This browser's localStorage: qm-drills, qm-history (append only), qm-major, qm-seq. Nothing is sent to a server. Stats aren't stored; they're computed from the history. A run with no answers isn't logged.
One run record:
{"start": 1790963315.07, "drill": "75x2d", "mode": "bench", "count": 20,
"done": 20, "right": 19, "total": 96.4,
"questions": [{"q": "75 × 48", "a": "3,600", "given": "3600", "ok": true, "t": 3.21}]}
Pegs, memory and sequences: /en/major-system/