1.) Which two numbers on the number line have an absolute value of 1?

Absolute value is defined as the distance of a number from zero on a number line.

Since, the distance can never be negative, hence, absolute value can never be negative.

For example 1 is 1 away from the origin and - 1 is also, 1 away from the origin.

Therefore, absolute value of both - 1 and 1 is 1. Mathematically, we can write

|-1| = 1

|1|=1

Therefore, the number 1 and - 1 on the number line have an absolute value of 1.