Addition & subtraction strategies to solve two-digit equations using an open number line. In this lesson, students go over using different addition and subtraction strategies to solve two-digit ...

Space to play or pause, M to mute, left and right arrows to seek, up and down arrows for volume. This is a number line. Hmm. Where should these numbers go? Let's start with the number 50. It's right ...

Newborn babies seem to have a rudimentary sense of numbers, preferring smaller numbers on the left and larger ones on the right. The finding suggests that this left-to-right mental number line might ...