Create your own centimeter ruler. Then, estimate and measure with lengths with it. Warm up with a Mystery Math Mistake as you add two 2-digit numbers using a decomposition strategy. Think through ...

Admit it, the iPhone in your pocket is like a Swiss Army Knife - it’s easy to carry and has a tool for almost every job; oh yeah, and it makes phone calls too. A ruler isn’t something you need all the ...

A revolutionary kind of laser light called an optical frequency comb makes possible a more precise type of atomic clock and many other applications Editor's note: This story was originally posted in ...