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.

The pupillary distance (PD) measurement is a requirement for people who want to purchase eyeglasses. Here, find out how to measure your PD using a mirror and a ruler.

It’s meant for measuring objects and that’s exactly what it does. When you need to measure something ‘in a pinch’, Ruler App is there. The makers of Ruler 2 are also having a contest - “In celebration ...