How to Learn the Square Numbers
Knowing your squares up to 20 by heart speeds up algebra, mental math, and any exam with a no-calculator section. The squares from 1 to 12 come with the times tables; 13 to 20 are the ones worth drilling. This deck covers all twenty.
There are 20 cards in the deck below. You can read through them, practise them right here with the flip-card player, and then save the deck to study properly with spaced repetition — the method that makes them stick for months, not minutes.
Why the square numbers from 1 to 20 is hard to memorize (and the fix)
Past 12², the pattern is less familiar (13² = 169, 17² = 289) and these are exactly the ones that slow you down in algebra and Pythagoras problems.
The fix is active recall plus spaced repetition. Instead of re-reading the list (which feels productive but barely works), you test yourself — pull each answer out of memory — and you review each card on a schedule that stretches over time. Every time you successfully recall a fact, the memory gets stronger and the next review is pushed further out. That's how you go from "I saw it once" to "I just know it."
The fastest way to learn the square numbers from 1 to 20
- Break it into small batches. You likely know 1–12 already. Focus your reviews on 13² through 20², the ones that are not part of the standard times tables.
- Test, don't re-read. Look at the question, say the answer out loud before flipping the card. The little struggle to recall is what builds the memory — a smooth re-read does almost nothing.
- Review on a schedule. Spaced repetition shows you each card right before you'd forget it. Get one right and it comes back in a few days, then a week, then a month. Miss one and it comes back sooner.
- Keep sessions short and daily. Five to ten minutes a day beats a two-hour cram every time. Consistency is the whole game.
One fact per card. Learn them both ways — the square of a number, and recognising a number as a perfect square.
The full deck: the Square Numbers
Here's every card in the set. Practise them above, or save the deck and let spaced repetition schedule your reviews automatically.
| Problem | Answer |
|---|---|
| 1² = ? (what is 1 squared?) | 1 |
| 2² = ? (what is 2 squared?) | 4 |
| 3² = ? (what is 3 squared?) | 9 |
| 4² = ? (what is 4 squared?) | 16 |
| 5² = ? (what is 5 squared?) | 25 |
| 6² = ? (what is 6 squared?) | 36 |
| 7² = ? (what is 7 squared?) | 49 |
| 8² = ? (what is 8 squared?) | 64 |
| 9² = ? (what is 9 squared?) | 81 |
| 10² = ? (what is 10 squared?) | 100 |
| 11² = ? (what is 11 squared?) | 121 |
| 12² = ? (what is 12 squared?) | 144 |
| 13² = ? (what is 13 squared?) | 169 |
| 14² = ? (what is 14 squared?) | 196 |
| 15² = ? (what is 15 squared?) | 225 |
| 16² = ? (what is 16 squared?) | 256 |
| 17² = ? (what is 17 squared?) | 289 |
| 18² = ? (what is 18 squared?) | 324 |
| 19² = ? (what is 19 squared?) | 361 |
| 20² = ? (what is 20 squared?) | 400 |
Save this deck and actually remember it
Create a free account, keep this 20-card deck, and we'll schedule every review at the perfect moment. First deck free forever — no credit card.
Study this deck free →FAQ: learning the square numbers from 1 to 20
How long does it take to learn the square numbers from 1 to 20?
Most people can lock in the square numbers from 1 to 20 within one to three weeks of short daily sessions. With spaced repetition doing 10–20 cards a day, you'll recognise them within days and recall them reliably within a couple of weeks.
What's the best way to memorize the square numbers from 1 to 20?
Active recall plus spaced repetition. Test yourself instead of re-reading, and review on a schedule that spaces the cards out over time. Flashcards are built for exactly this — which is why the deck above is the fastest path.
Is this deck free?
Yes. You can practise all 20 cards on this page for free with no account. Sign up (also free) to save the deck and let spaced repetition schedule your reviews so it sticks long-term.