Answer
The blue dot indicates the graph of the number.
Work Step by Step
The distance from 0 to 1 is called the unit distance.
Numbers to the right of the origin (0) are positive and numbers to the left of the origin are negative.
Real numbers are graphed on a number line by placing a dot at the correct location for each number.
The number $-3.4=-3\displaystyle \frac{2}{5}$ is negative, and is located $3,4$ units to the left of 0.
Or, $0.4$ (two fifths of the unit distance) to the left of $-1$.
