Special vocabulary used in this lesson: Subtraction, Number line, Counting-back ... Remember to use the biggest number first! Download this worksheet to help you with the counting back strategy.

Subtraction is taking away one number from ... For example, what is the difference between 10 and 7? Let's use a number line to help. Start with the smaller number and then count on.

go up the number line (move to the right). When subtracting a positive number, go down the number line (move to the left). Start at \(3\) and go down \(10\). The answer is \(- 7\).