Stage: 2 Challenge Level: 
It might be useful to round the percentages up or down to estimate the value of the balls.
You could think of a percentage as a fraction or decimal.
Addition & subtraction. Investigations. Calculating with percentages. Interactivities. Estimating and approximating. Place value. Odd and even numbers. Percentages. Multiplication & division. Comparing and Ordering numbers.
Published June 2002,June 2009.
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