Stage: 3 Challenge Level: 
Why not try some different class sizes first?
As 60% of the group got one question correct and 70% the other what does this tell you about the percentage that got both right?
Calculating with percentages. Percentages. Integers. Patterned numbers. Venn diagrams. Properties of numbers. Calculating with fractions. Multiplication & division. Fractions. Factors and multiples.
Published September 2001.
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