Shuffle the practice set

In a blocked practice set, students never have to decide which method applies; the page heading decides for them. Interleave problems from different topics and accuracy drops during practice but rises sharply at test, because choosing the method is most of the skill (Rohrer & Taylor, 2007). For checking understanding, that's the point: on a shuffled set, a correct answer finally tells you they recognised the problem type, not just executed it.

In practice

• Don't interleave on day one. Block while the method is new; shuffle once they can execute it.
• Mix confusable neighbours deliberately: area with perimeter, affect with effect, the two formulas everyone swaps.
• Warn students it will feel harder and slower. That feeling is the desirable difficulty doing its job, and saying so stops them reading it as failure.