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They are mixture of topic questions, based on specific GCSE grade levels.
There are more interleaving resources on my mathslinks website.
Find out more about interleaving maths practice and why I feel it so important here.
Here you can learn more about how I use interleaving in my teaching.
Grade 1 (Non Calc) Sheet A : Solutions
Grade 1 (Non Calc) Sheet B : Solutions
Grade 1 (Calc) Sheet A : Solutions
Grade 1 (Calc) Sheet B : Solutions
Grade 1 (Calc) Sheet D : Solutions
Grade 1 (Calc) Sheet E : Solutions