How to Learn the Square Roots
A square root asks "what number times itself gives this?" — √16 is 4. Knowing the square roots of the perfect squares by heart speeds up algebra, geometry (Pythagoras) and mental math. This deck drills them, plus what a square root actually means.
There are 12 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 roots is hard to memorize (and the fix)
Recognising a perfect square instantly (that 144 = 12²) is the slow part for most people, and irrational roots (√2) are often misunderstood. Learning the perfect squares fixes both.
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 roots
- Break it into small batches. Learn the square roots of the perfect squares up to 144 (√1 to √144), since these come up constantly.
- 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. Every positive number has two square roots (+ and −), but the √ symbol means the positive one.
The full deck: the Square Roots
Here's every card in the set. Practise them above, or save the deck and let spaced repetition schedule your reviews automatically.
| Question | Answer |
|---|---|
| What does a square root ask? | "What number times itself gives this?" |
| What is √4? | 2 |
| What is √9? | 3 |
| What is √16? | 4 |
| What is √25? | 5 |
| What is √49? | 7 |
| What is √64? | 8 |
| What is √81? | 9 |
| What is √100? | 10 |
| What is √144? | 12 |
| What is √2 (approximately)? | About 1.41 (it is irrational) |
| What is a "perfect square"? | A number whose square root is a whole number (like 36) |
Save this deck and actually remember it
Create a free account, keep this 12-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 roots
How long does it take to learn the square roots?
Most people can lock in the square roots within one to three weeks of short daily sessions. With spaced repetition doing 10–12 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 roots?
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 12 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.