Remember that when you find a factor you should find the other number in the factor pair. The divisibility rules can be used to show that 1, 2, 3, 5, 6, and 10 are factors (and that 4 and 9 are not). Use factor pairs to find more factors: 15, 25, 30, 50, 75, and 150. Use division to check 7, 8, 11, 12, and 13. Since $\displaystyle{150}\div{13}\usepackage{cmbright}\Huge\$ is less than 13, stop. The correct answer is 1, 2, 3, 5, 6, 10, 15, 25, 30, 50, 75, and 150.