You may also like

problem icon


Three children are going to buy some plants for their birthdays. They will plant them within circular paths. How could they do this?

problem icon

Forgot the Numbers

On my calculator I divided one whole number by another whole number and got the answer 3.125 If the numbers are both under 50, what are they?

problem icon

Junior Frogs

Have a go at this well-known challenge. Can you swap the frogs and toads in as few slides and jumps as possible?

Curious Number

Stage: 2 Challenge Level: Challenge Level:3 Challenge Level:3 Challenge Level:3

Do you know any divisibility rules?
A number is divisible by $3$ if its digits, when added together, are divisible by $3$. For example, take $174: 1 + 7 + 4 = 12$ which is divisible by $3$. You can add it as many times as you want. $12: 1 + 2 = 3$
A number is divisible by $6$ if it is an even number and it is divisible by $3$.
A number is divisible by $4$, if the tens and units form a number which is divisible by $4$, for example $732$ and $9048$ are divisible by $4$ (because $32$ and $48$ are divisible by $4$, but $338$ and $2342$ are not (because $38$ and $42$ are not divisible by $4$). (Why does this work?)
It could be a good idea to make a table to keep track of where the digits $1$ to $6$ could go. 
Where will the even numbers have to go?
So what about the odd numbers?
Where will the $5$ have to go?