I learned something surprising this weekend. A rule I was taught back in elementary school turned out not always to be true. In the process, I discovered something worrisome about myself and how we ...

Rounding up a number always results in a figure that is equal to or larger than the original number. As an example, if you were computing the number of employees you needed to accomplish a project, ...

Use place value cards to practice rounding numbers to the nearest ten and hundred. Warm up with a Mystery Math Mistake to hunt for the mistake made counting up on the number line. Use place value ...