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Simple counting exercise, with combinations

Introduction to counting with permutations and combinations

Introduction to counting with permutations and combinations

Intorduces strong induction and uses it to verify the solutions of a second order linear recurrence.

Writing equations

Solving equations for x

Rearranging equations/making x the subject

Simplifying equations/collecting like terms

Using BIDMAS rules to solve equations

Given a statement in words of a relationship between two variables, write down a corresponding formula. It's marked correct if values satisfying the relationship satisfy the formula, and values not satisfying the relationship don't.

Then, given a value for one of the variables, work out the value of the other one. They're substituted into the formula given in the first part and marked correct if it's satisfied.

Both parts use custom marking algorithms.