1. Problem statement: Represent the magnitude of the number -8 using tiles as in the picture. A red tile denotes a negative unit and a yellow tile denotes a positive unit. 2. Formula and important rules: The magnitude (absolute value) of a number $x$ is $|x|$ which equals the distance of $x$ from 0 on the number line. Therefore $|x|$ is always nonnegative. Important rule: The color indicates the sign but does not affect the magnitude. 3. Calculation: Compute the absolute value $|-8|$. We evaluate: $|-8| = -( -8 ) = 8$. 4. Tile representation: Because -8 is negative we use 8 red tiles. Arrange them in two columns of 4 to match the picture with 4 red dots in the left column and 4 red dots in the right column. 5. Final answer: The magnitude of -8 is 8. Thus the picture correctly shows 8 red tiles representing $|-8| = 8$.