Divisibility

problem
Favourite

Fac-Finding

Age

14 to 16

Challenge level

2 out of 3

Lyndon chose this as one of his favourite problems. It is accessible but needs some careful analysis of what is included and what is not. A systematic approach is really helpful.
problem
Favourite

Odd Stones

Age

14 to 16

Challenge level

2 out of 3

On a "move" a stone is removed from two of the circles and placed in the third circle. Here are five of the ways that 27 stones could be distributed.
problem
Favourite

What an Odd Fact(or)

Age

11 to 14

Challenge level

3 out of 3

Can you show that 1^99 + 2^99 + 3^99 + 4^99 + 5^99 is divisible by 5?
problem
Favourite

Share Bears

Age

5 to 7

Challenge level

1 out of 3

Yasmin and Zach have some bears to share. Which numbers of bears can they share so that there are none left over?
problem
Favourite

Statement Snap

Age

7 to 11

Challenge level

1 out of 3

You'll need to know your number properties to win a game of Statement Snap...
problem
Favourite

Division Rules

Age

7 to 11

Challenge level

1 out of 3

This challenge encourages you to explore dividing a three-digit number by a single-digit number.
problem
Favourite

Neighbours

Age

7 to 11

Challenge level

2 out of 3

In a square in which the houses are evenly spaced, numbers 3 and 10 are opposite each other. What is the smallest and what is the largest possible number of houses in the square?
problem
Favourite

Curious Number

Age

7 to 11

Challenge level

3 out of 3

Can you order the digits from 1-3 to make a number which is divisible by 3 so when the last digit is removed it becomes a 2-figure number divisible by 2, and so on?
game
Favourite

The Remainders Game

Age

7 to 14

Challenge level

1 out of 3

Play this game and see if you can figure out the computer's chosen number.
problem
Favourite

Dozens

Age

7 to 14

Challenge level

1 out of 3

Can you select the missing digit(s) to find the largest multiple?