Intro to negative numbers

Here's a number line that should look very familiar. It starts at $0$0, then counts up by $1$1 from there:

We know that if we were to keep going to the right, we would have $11$11, then $12$12, and so on.

What happens if we keep going to the left of $0$0 though? We get negative numbers! To the left of $0$0 is $-1$minus, 1, then $-2$minus, 2, then $-3$minus, 3, and so on:

Negative numbers help us describe values less than zero.

When the temperature is $8^\circ$8, degrees below $0^\circ$0, degrees, it is less than $0$0. We can say the temperature is $-8^\circ$minus, 8, degrees.