![Placeholder: several colourful numbers](/themes/nrich/images/nrich_small_placeholder.png)
list
All Secondary Factors and Multiples
Here is a list of all the secondary problems connected with Factors and Multiples
![Counting Factors](/sites/default/files/styles/medium/public/thumbnails/content-97-01-six1-icon.jpg?itok=k7J5c7_5)
![Differences](/sites/default/files/styles/medium/public/thumbnails/content-98-10-six3-icon.png?itok=o6pNw4ut)
problem
Differences
Can you guarantee that, for any three numbers you choose, the product of their differences will always be an even number?
![Power mad!](/sites/default/files/styles/medium/public/thumbnails/content-id-6401-icon.png?itok=Ukk2Xjef)
problem
Power mad!
Powers of numbers behave in surprising ways. Take a look at some of these and try to explain why they are true.
![How much can we spend?](/sites/default/files/styles/medium/public/thumbnails/content-id-6650-icon.png?itok=VYEcWe-l)
problem
How much can we spend?
A country has decided to have just two different coins, 3z and 5z
coins. Which totals can be made? Is there a largest total that
cannot be made? How do you know?