Factors, common factors and HCF
Factors
There are lots of well structured exercises in this CIMT chapter which I had in reserve for stretch if it was needed.
Number Games for Students Aged 11-13
The second game on here (Factors game) is one I used as a plenary in one of the lessons and it worked really, really well.
Millionaire factors and divisibility game
The children found this game a bit boring when I gave it to them to play in a computer classroom but when I did it as a whole class starter recap of a previous lesson it worked really well.
Factors game
The Manga High games are really top quality and this factors game was a real hit with the children. You need to check that you will be able to run it inside your school as sometimes firewalls need a small configuration change to run the interactives. Email Manga High and they'll send you the details.