This document contains mathematical expressions involving finding the highest common factor (HCF) of different pairs of numbers. It lists expressions for squaring numbers and multiplying numbers, followed by examples of finding the HCF of 12 & 18, 30 & 20, and 40 & 100.

2. 2²=

3. 3² =

4. 2² x 3² =

5. 5² x 2² =

6. HCF of 12 & 18 =

7. HCF of 30 & 20

8. HCF of 40 & 100