Prime Factor Form

There are many ways to introduce and express numbers as a product of prime factors but recently I have been looking at questions that use prime factor form.

I’m not including HCF or LCM in this because most teachers have used PFF to solve HCF and LCM problems before.

Here are some questions I have written that can be solved easily using PFF


These are on the ppt below

Prime Factor Form

I also like this activity I made, its simple practice but saves paper if you display it as a ppt

pff4Primes and Prime Factors


I made this starter to use with year 10

Prime Factor Form Questions

Screen Shot 2017-11-07 at 21.48.42Screen Shot 2017-11-07 at 21.48.53Screen Shot 2017-11-07 at 21.49.01

UPDATE! Prime Factor Form Challenge. The idea is students are faced with increasingly more challenging PFF questions. They need to think about divisibility to help them and they know the numbers are listed below. It can generate some interesting discussions about numbers/divisibility. Students who are faced with a large number that isn’t divisible by 2, 3 or 5 may believe the remainder is a prime number. Once the number is written in PFF they can asign the correct letters and unscramble the word.


Here is the ppt for PFF pff


Screenshot 2020-08-16 at 08.38.05Prime Factor Questions

Screenshot 2020-08-17 at 23.11.06Screenshot 2020-08-17 at 23.10.58Screenshot 2020-08-17 at 23.10.52Prime Factors

I was thinking about the factors particular numbers and considered how many factors int he numbers from 1-40. When I reached the 30s I was surprised how many numbers could be written as a product of two primes, meaning they have 4 factors in total. So I started wondering about what students would make of it. Would they realise if the number was written as a product of two primes it would have 4 factors and would they realise you could easily find a number with 4 factors by multiplying 2 primes together.






One thought on “Prime Factor Form

Leave a Reply

Fill in your details below or click an icon to log in: Logo

You are commenting using your account. Log Out /  Change )

Facebook photo

You are commenting using your Facebook account. Log Out /  Change )

Connecting to %s