1. What number is he thinking of? 2x = x + 4 so x = 4 (a) 2x + x = 39
Using equations
A2.2 Core Plenary
Write down a story which fits each of these equations. Solve the equation.
For example 2x = x + 4
Sam thinks of a number.
If he doubles the number, he gets the same answer as if he adds 4 to the number.
What number is he thinking of?
2x = x + 4 so x = 4
(a) 2x + x = 39
(b) x – 4 + x = 24
(c) x + 2x + 3x + 4x = 360
Preamble
Activities such as these give pupils the opportunity to explore linear equations and to show evidence of any grave algebraic misconceptions.
Possible content
Forming algebraic equations.
Resources
None.
Solution/Notes
Pupils own stories to match the given equations.
(a) x = 13 (b) x = 14 (c) x = 36
Original Material © Cambridge University Press 2009
Original Material © Cambridge University Press 2009