Stage: 3 and 4 Challenge Level: 
Jo has three numbers which she adds together in pairs.
When she does this she has three different totals: $11$, $17$ and $22$
What are the three numbers Jo had to start with?
Can you describe a method that would enable you to work out the three numbers given any three totals?
Polynomials. Making and proving conjectures. Manipulating algebraic expressions/formulae. Mathematical reasoning & proof. Trial and improvement. Inequality/inequalities. Factorisation (algebraic). Simultaneous equations. Creating expressions/formulae. Generalising.
Published December 2002.
Copyright © 2007. University of Cambridge. All rights reserved.
NRICH is part of the family of activities in the Millennium Mathematics Project, which also includes the Plus and Motivate sites.
email: nrich@damtp.cam.ac.uk
