Spaced Repetition: Why 5 Minutes a Day Beats an Hour

It feels as if a long practice session should be more effective than a short one. But the research on memory points the other way: when you practise matters more than how long. Spaced repetition is the simple idea behind that, and it's the main reason short, daily practice works so well for times tables.

What is the forgetting curve?

In the 1880s the German psychologist Hermann Ebbinghaus tested his own memory for lists and found that forgetting is fast at first, then slows down. Much of what he learnt was gone within a day or two, unless he reviewed it. Each review made the memory fade more slowly. That pattern, the forgetting curve, has been confirmed many times since.

For a child learning 7 × 8 on Monday, it means the fact is fragile on Tuesday. A quick review then strengthens it; without one, it's often gone by Friday.

How does spacing beat cramming?

Cramming (lots of practice in one go) gives a good result at the end of the session, which is why it feels effective. But the knowledge fades quickly. Spreading the same practice over several days gives weaker-feeling sessions and much better long-term memory. This spacing effect is one of the most robust findings in learning research.

	One hour on Sunday	Nine minutes a day
Total time	60 minutes	63 minutes
Reviews per fact	Many, all at once	Spread over the week
A week later	Much forgotten	Much more remembered

How do the gaps grow?

A newly learnt fact might be reviewed the next day, then after three days, then a week, then a few weeks. Each time it's remembered, the gap can grow. Each time it's forgotten, it goes back to daily review. Hard facts naturally get more practice; easy ones get out of the way.

How does smart practice use this?

Our smart practice is built on a spaced-repetition method called SM-2, adapted for children. It tracks every fact on its own, not whole tables:

• Answered correctly and quickly → the gap grows faster.
• Answered correctly but slowly → the gap grows more gently.
• Answered wrongly → back to tomorrow, and repeated later in the same session.

Each session mixes facts that are due, a few new ones, and the weakest ones. The result is a short session that spends its time where it's needed. The My Progress page shows which facts are due.

How can you use spaced repetition without an app?

The three-pile flashcard method (sometimes called the Leitner system) works well:

1. Print times tables flashcards and make three piles: New, Getting there, Known.
2. Review New every day, Getting there every three days, Known once a week.
3. A correct answer moves a card up a pile; a wrong answer sends it back to New.

What else makes practice stick?

• Mixed order rather than reciting in sequence.
• Recalling rather than reading: trying to remember is what strengthens memory.
• Calm: see maths anxiety in children.
• Sleep: memories are consolidated overnight, another reason daily practice works.

For a complete plan, read how to learn times tables, and if facts keep slipping, see what helps when a child can't remember times tables.

Spaced practice also suits the Year 4 Multiplication Tables Check (start months ahead rather than cramming), and it works just as well with times table games mixed in.