Debt Recovery
Age 11 to 14 Short Challenge Level:
Tony and Tina can't work out which of them owes what to the other. Can you?
Tick Tock
Age 11 to 14 Short Challenge Level:
Tick's watch is slow and Tock's watch is fast. How long is it before their watches differ by an hour?
Loose Change
Age 11 to 14 Short Challenge Level:
In how many ways can you give change for a ten pence piece?
Paying the Bill
Age 11 to 14 Short Challenge Level:
Gill and I went out to lunch. We agreed to split the total cost equally. How much did I owe Gill?
Mathematical Ages
Age 11 to 14 Short Challenge Level:
Arrange these three famous mathematicians in order with the shortest-lived first.
Quiz Questions
Age 11 to 14 Short Challenge Level:
Jack does a 20-question quiz. How many questions didn't he attempt?
Mini Kakuro
Age 11 to 14 Short Challenge Level:
The sum of each column and row in this grid give the totals as shown. What number goes in the starred square?
Reverse Ages
Age 11 to 14 Short Challenge Level:
When is the next time that Brian's age will be the reverse of his father's age?
Highs and Lows
Age 11 to 14 Short Challenge Level:
What were the maximum and minimum temperatures recorded in my max/min thermometer?
Central Sum
Age 11 to 14 Short Challenge Level:
Can you find numbers between 100 and 999 that have a middle digit equal to the sum of the other two digits?
Negative Dice
Age 11 to 14 Short Challenge Level:
If the odd numbers on two dice are made negative, which of the totals cannot be achieved?
Alberta's Age
Age 11 to 14 Short Challenge Level:
Alberta won't reveal her age. Can you work it out from these clues?
Double with 1 to 9
Age 11 to 14 Short Challenge Level:
Can you find a number and its double using the digits $1$ to $9$ only once each?
Sum Up
Age 11 to 14 Short Challenge Level:
David listed ten consecutive numbers and removed one of them. Which number did he remove?
Missing 9s
Age 11 to 14 Short Challenge Level:
Sara makes a list of the whole numbers that do not contain any 9s. What is the 300th number on her list?
Itchy's Fleas
Age 11 to 14 Short Challenge Level:
Itchy the dog has a million fleas. How many fleas might his shampoo kill?
Even Squares
Age 11 to 14 Short Challenge Level:
Can you find squares within a number grid whose entries add up to an even total?
Digit Sum Puzzle
Age 11 to 14 Short 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?
Repeat Product
Age 11 to 14 Short Challenge Level:
Can you work out the value of P+Q+R in the multiplication shown?
Equal Length Powers
Age 14 to 16 Short Challenge Level:
How many positive integers $n$ exist for which $n^2$ has the same number of digits as $n^3$?
Pros and Cons
Age 14 to 16 Short Challenge Level:
If p is a positive integer and q is a negative integer, which of these expressions is the greatest?
Number Crunch
Age 14 to 16 Short Challenge Level:
Create 24 numbers from four digits. Why is 101 always a factor of their sum?
NRICH is part of the family of activities in the Millennium Mathematics Project.