This lesson will demonstrate how to add/subtract measurements and report the result to the correct number of significant digits. It is 2 of 3 in the series titled "Adding and Subtracting Using Significant Figures."

A guided lesson explaining how to add and subtract numbers expressing the answer with the appropriate number of significant digits.

You can use an abacus to count, add, subtract, multiply and more. Try this interactive abacus and see if you can make the numbers. Choose "here's more" for some clues. Good luck!

A map from 1903 of the United States showing the time zones as they were then established. "The heavy dotted line shows the arbitrary divisions of time in the United States. The plus and minus marks on either side of the meridian lines...