Protocol
Mix problems so the method is no longer announced
A page titled 'Use this formula' has already solved part of the problem for you.
When it fits
- You can solve a chapter's exercises but struggle to choose a method on a mixed test.
When to avoid it
- The cited evidence concerns mathematics. Beginners may still need explanation and supported examples before mixed practice.
Why it matters
Once basic methods are understood, mix suitable problem types so each question requires choosing a strategy. A classroom mathematics trial found better delayed performance with interleaved practice. The useful difficulty is selecting the method from the problem itself—not switching randomly between unrelated activities.
Steps
- Choose several relevant problem types you have been taught.
- Mix them without headings that reveal the required method.
- Explain the method choice before calculating and review selection errors separately.
An example
A practice sheet can mix percentage change, proportions and averages rather than giving a labeled block for each.
Check your result
You choose an appropriate method on a new unlabeled problem, not only execute a named procedure.
Keep this limit in mind
- The cited evidence concerns mathematics. Beginners may still need explanation and supported examples before mixed practice.
Evidence and sources
A mathematics classroom trial found better delayed test performance after interleaved practice requiring students to select the relevant strategy.
Evidence from the tested mathematics setting is not a reason to alternate unrelated tasks every few seconds.
A Randomized Controlled Trial of Interleaved Mathematics Practice · Abstract and Educational Impact statement