University of Georgia
University of Georgia: Intermath Dictionary: Additive Inverse
"What happens when you add opposite numbers together?" Understanding the additive inverse will help you to answer this questions. An explanation of additive inverse with examples and non-examples.
PBS
Pbs: Balancing Scales to Solve Equations
Predict the number of blocks you need to equal the weight of one bag and then test your theory. This interactive exercise focuses on using critical thinking skills to add and subtract items on the scales to achieve balance and visual...
University of St. Andrews (UK)
University of St. Andrews: Johann Heinrich Lambert
This page, which is provided by the University of St Andrews, offers a short biography on Johann Heinrich Lambert, a French-German mathematician (1728-1777.) It discusses his life and his contributions to mathematics.