Enrichment in Mathematics - Algebra
Consecutive Numbers
Teachers Notes
This activity could be used as a starter or plenary. Although a closed activity in
that it has a specific numerical solution, pupils can be encouraged to discuss
their methods for working out the answer.
It revises the use of algebra to form and solve a problem.
Solution
If the first number is called a, then the next 4 consecutive numbers can be
written as a + 1, a + 2, a + 3, a + 4
We know that their total is 162 after doubling the middle number, so
a + a + 1 + 2(a + 2) + a + 3 + a + 4 = 162
So 6a + 12 = 162
6a = 150
a = 25
So the middle number is 27
As an extension, pupils can be asked to write a similar problem for a partner,
then swap and try to solve each other’s.
Worcestershire Numeracy Team
Enrichment Activities
Enrichment in Mathematics - Algebra
Consecutive Numbers
Five consecutive numbers add up to 162 after the
middle number has been doubled.
What is the middle number?
Worcestershire Numeracy Team
Enrichment Activities