problem
Quiz questions
Age
11 to 14
Challenge level
Jack does a 20-question quiz. How many questions didn't he attempt?
problem
Jenny's logic
Age
11 to 14
Challenge level
Weekly Problem 52 - 2009
How did Jenny figure out that Tom's cards added to an even number?
How did Jenny figure out that Tom's cards added to an even number?
problem
Mini Kakuro
Age
11 to 14
Challenge level
The sum of each column and row in this grid give the totals as shown. What number goes in the starred square?
problem
Newspaper sheets
Age
14 to 16
Challenge level
From only the page numbers on one sheet of newspaper, can you work out how many sheets there are altogether?
problem
Central sum
Age
11 to 14
Challenge level
Can you find numbers between 100 and 999 that have a middle digit equal to the sum of the other two digits?
problem
12345
Age
14 to 16
Challenge level
Repeat a pattern of numbers to form a larger number. Can you find the sum of all the digits?
problem
Digit deletion
Age
11 to 14
Challenge level
What is the largest number of digits that could be erased from this 1000-digit number, to get a surprising result?
problem
Alberta's age
Age
14 to 16
Challenge level
Alberta won't reveal her age. Can you work it out from these clues?
problem
Double with 1 to 9
Age
11 to 14
Challenge level
Can you find a number and its double using the digits $1$ to $9$ only once each?