One+number+as+a+fraction+of+another

1. **Writing a fraction in its lowest terms**
 * How do we know if a fraction is in its lowest terms?
 * How do we cancel a fraction to its lowest terms?
 * 15/20 - what is the highest common factor of 15 & 20? What would it cancel to?
 * What about 160/240? What would it cancel to?
 * You can find the highest common factor by cancelling in steps e.g. by halving it, and then doing it again
 * or, you could find their prime factors and multiply the ones they share e.g. 160 & 240 would be 2x2x2x2x5

2. **Writing fractions in the same units**

3. **Challenge!**
 * In this challenge you will not be asked to give me the answer. I have already given you the answer.
 * You need to tell which question the answer is from: [|Fractions What is the question.pptx]