Question Video: Evaluating the Addition of Rational Numbers by Sketching a Number Line Mathematics • First Year of Preparatory School

Video Transcript

Fill in the blank using the number line. Negative 0.6 plus what is equal to 0.1.

In this question, we want to find the missing value in an equation by using the number line. We should start by sketching the number line. We want the values in the equation to appear on the number line. We can note that negative 0.6 is negative six times 0.1. So we want to include increments of 0.1 on the number line. This gives us the following number line.

We can then recall that we can add numbers together on a number line by using displacements. In particular, if negative 0.6 plus 𝑏 is equal to 0.1, then 𝑏 is the displacement traveling from negative 0.6 to 0.1. We can see that the displacement is seven increments of 0.1 in the positive direction, so 𝑏 is 0.7. Hence, by using the number line, we have shown that negative 0.6 plus 0.7 is equal to 0.1.