One approach is to convert them to decimal using your calculator or long division:
3/4 = 0.75
7/9 ≈ 0.78
1/2 = 0.50
2/3 ≈ 0.67
Since the number line has 0.1 increments, you can place each value in between the right increments. For instance 3/4 you place between 0.7 and 0.8. You place it halfway because 0.75 is halfway between 0.7 and 0.8. It's ok to estimate the exact location in this case.
