Students investigate the Food Pyramid by constructing a creative project known as a Food Pyramid Abacus. They correlate the color beads withe each food group and the number of recommended servings from each. The abacus is a learning tool...

This applet explores the use of an abacus model for representing numbers and for performing addition.

This site presents a pictorial timeline of technology developments.

Use the diagram on this one page website to solve the problem. There are teacher notes and the solution is only a click away.