Study techniques5 min read·

Interleaving: Why Mixing Topics Beats Practising One at a Time

Doing 20 questions of the same type feels efficient. Mixing different types feels messy. The messy way wins on test day.

Blocked Versus Interleaved Practice

Blocked practice means doing one type of problem over and over: 20 questions on percentages, then 20 on ratios. Interleaved practice mixes them: percentage, ratio, probability, percentage, geometry.

Blocked practice feels better. You find a rhythm, you get faster, and your score in that session is high. But in an exam, questions are not labelled by chapter. The hard part is often recognising which method a question needs, and blocked practice never trains that skill.

What the Research Shows

In a study by Rohrer and Taylor, students who practised mixed maths problems scored much higher on a later test than students who practised in blocks, even though the mixed group did worse during practice. Similar results have been found in other areas, including learning to tell apart painting styles and bird species.

Why It Works

  • It trains choosing the method, not just applying it.
  • It forces comparison. Seeing different types side by side highlights what makes each one different.
  • It adds spacing. Coming back to a topic after a gap is a mini spaced repetition.

    • How to Interleave

  • Learn each topic first. Interleaving is for practice, not for first contact with brand-new material.
  • Make mixed sets. Once you have covered three or four related topics, practise them together in random order.
  • Shuffle your flashcards across chapters instead of keeping them in decks by chapter.
  • Use past papers. Full papers are naturally interleaved.

    • Expect It to Feel Harder

    Your practice scores will drop at first. That is normal and is not a sign it is failing. Judge it by how you do on mixed, timed tests a week later.

    The Bottom Line

    Practise like the exam: mixed, unlabelled and timed. Log your accuracy per topic in myExamRoutine so that mixed sets still show you which topics drag your score down.

    Turn your syllabus into a tracker

    myExamRoutine tracks every topic of your syllabus, plans your study days and shows your weak areas. Try it free for 15 minutes.

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