Home Back to the Challenge Answer Try These Did You Know? Try Another Challenge  
Think About This
Figure This!
 

You cannot add percentages unless: they were calculated using the same population and are measuring mutually exclusive events.

When can you add, subtract, multiply, or divide percentages?

 

 

Washington DC’s population changed by –14.5% from April 1, 1990 to July 1, 1999.

Is it ever possible to have a percentage over 100?

 
Home · Back to the Challenge · Answer · Try These · Did You Know? · Resources
Try Another Challenge · Challenge Index · Math Index · Printing the Challenges · En Español
Family Corner · Teacher Corner · About Figure This! · Purchase the CD
©2004 National Council of Teachers of Mathematics
Web site and CD-ROM design/production
© 1999-2004 KnowNet Construction, Inc.