Question 16:
State the first two common multiples of 3, 5 and 6.

Solution:
Multiples of 3 = 3, 6, 9, 12, 15, 18, 21, 24, 27, 30, 33, 36, 39, 42, 45, 48, 51, 54, 57, 60, …
Multiples of 5 = 5, 10, 15, 20, 25, 30, 35, 40, 45, 50, 55, 60, …
Multiples of 6 = 6, 12, 18, 24, 30, 36, 42, 48, 54, 60, …

The first two common multiples of 3, 5 and 6 are 30 and 60.

Question 17:
Find the lowest common multiple (LCM) of 4, 8 and 24.

Solution:

Question 18:
Find the lowest common multiple (LCM) of 8, 12 and 15.

Solution:

Question 19:
Find the highest common factor (HCF) of 26, 52 and 156.

Solution:

Question 20:
Given that (m + 5) is the highest common factor of 81 and 108, find the value of m.

Solution:

Question 11:
State all the prime factors of 156.

Solution:
$\begin{array}{l}\text{Factors of }156:\\ 1\times \text{ 156}\\ \boxed{2}\times \text{ 78}\\ \boxed{3}\times \text{ 52}\\ \text{4 }\times \text{ 39}\\ \text{6 }\times \text{ 26}\\ \text{12 }\times \boxed{\text{13}}\\ \\ 2,3\text{ and }13\text{ are the prime factors of }156.\end{array}$

Question 12:
State all the prime factors of 182.

Solution:
$\begin{array}{l}\text{Factors of }182:\\ 1\times \text{ 182}\\ \boxed{2}\times \text{ 91}\\ \boxed{\text{7}}\times \text{ 26}\\ \boxed{13}\times \text{ 14}\\ \\ 2,\text{ 7, 13 and 91 are the prime factors of }182.\end{array}$