Answer:
3/9 - 1/9
Step-by-step explanation:
Given that:
Distance between successive tickmarks = 1/9
Length of blue line = 3 * (1/9)
Length of red line = 1 * (1/9)
The expression being modeled by the number line :
Length of blue line - length of red line
3 *(1/9) - 1(1/9)
3/9 - 1/9
(3 - 1) / 9
= 2/9
