GCSE Secondary Maths Age 13-17 - Ratio, Proportion & Rates of Change: Percentages - Explained

The video tutorial explains how to calculate 15% of 80 without a calculator. It starts by finding 10% of 80, which is 8, and then calculates 5% by halving 10%, resulting in 4. Adding these two results gives 15% of 80, which is 12. The tutorial also discusses the marks allocation for the method and final answer.

What method can be used to quickly find 10% of a number?

How many marks are awarded for the method and the final answer in this question?