Students put all of their addition and subtraction skills together to solve equations.

Subtraction Let’s take a look at subtraction now. Subtraction is where we know the whole and only one of the parts. So this question 12 – 5 = ? would look like this as a part-whole model.

Watch this video to learn some mental addition and subtraction strategies. This section contains videos from our educational partners, hosted by the BBC.

But what if the two vectors are not in the same direction and they are not perpendicular? Well, here is the key to vector addition: Every vector can be broken into two vectors.

Dutch mathematics programs emphasize mental addition and subtraction in the lower grades. For two-digit numbers up to 100, instruction focuses on "counting by tens from any number" (N10), a strategy ...