Challenge Level

Tony and Tina can't work out which of them owes what to the other. Can you?

Challenge Level

In how many ways can you give change for a ten pence piece?

Challenge Level

Arrange these three famous mathematicians in order with the shortest-lived first.

Challenge Level

Jack does a 20-question quiz. How many questions didn't he attempt?

Challenge Level

The sum of each column and row in this grid give the totals as shown. What number goes in the starred square?

Challenge Level

What were the maximum and minimum temperatures recorded in my max/min thermometer?

Challenge Level

When is the next time that Brian's age will be the reverse of his father's age?

Challenge Level

Can you find numbers between 100 and 999 that have a middle digit equal to the sum of the other two digits?

Challenge Level

If the odd numbers on two dice are made negative, which of the totals cannot be achieved?

Challenge Level

What is the smallest possible area that this rectangle could have?

Challenge Level

Tick's watch is slow and Tock's watch is fast. How long is it before their watches differ by an hour?

Challenge Level

Can you find a number and its double using the digits $1$ to $9$ only once each?

Challenge Level

Gill and I went out to lunch. We agreed to split the total cost equally. How much did I owe Gill?

Challenge Level

If it takes 852 digits to number all the pages of a book, what is the number of the last page?

Challenge Level

Sara makes a list of the whole numbers that do not contain any 9s. What is the 300th number on her list?

Challenge Level

Can you find squares within a number grid whose entries add up to an even total?

Challenge Level

Let N be the smallest positive integer whose digits add up to 2015. What is the sum of the digits of N+1?

Challenge Level

Can you work out the value of P+Q+R in the multiplication shown?

Challenge Level

David listed ten consecutive numbers and removed one of them. Which number did he remove?

Challenge Level

If p is a positive integer and q is a negative integer, which of these expressions is the greatest?

Challenge Level

How many positive integers $n$ exist for which $n^2$ has the same number of digits as $n^3$?

Challenge Level

Alberta won't reveal her age. Can you work it out from these clues?

Challenge Level

When the numbers from 1 to 1000 are written on a blackboard, which digit appears the most number of times?

Challenge Level

What is the sum of all the digits in all the integers from one to one million?

Challenge Level

If the numbers in this news article have been estimated, then what is the largest number of gorillas that there could have been 10 years ago?

Challenge Level

Create 24 numbers from four digits. Why is 101 always a factor of their sum?