Algebra 9

2 marks · Easy

Show, by using algebra, that the difference between two consecutive even numbers is always 2.

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Let two consecutive even numbers be 2n and 2n+2. Their difference is (2n+2)-(2n) = 2.

Also accept: Let even numbers be 2m, 2m+2, difference is 2

Common mistakes: Wrongly writing odd numbers or incorrect difference

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Marking points

M1 · 1 mark · Correctly expresses two consecutive even numbers algebraically (2n and 2n+2, or equivalent).

A1 · 1 mark · Correctly finds difference to be 2 and states conclusion.

Worked solution

Let two consecutive even numbers be 2n and 2n+2. The difference is (2n+2)-(2n)=2.