Pairing Up
The numbers 72, 8, 24, 10, 5, 45, 36, 15 are grouped in pairs so that each pair has the same product. Which number is paired with 10?
The numbers 72, 8, 24, 10, 5, 45, 36, 15 are grouped in pairs so that each pair has the same product. Which number is paired with 10?
How much lighter will £5 worth of 5p's be with these new lighter coins?
Each clue in this Sudoku is the product of the two numbers in adjacent cells.
Find the number which has 8 divisors, such that the product of the divisors is 331776.
Using some or all of the operations of addition, subtraction, multiplication and division and using the digits 3, 3, 8 and 8 each once and only once make an expression equal to 24.
Two numbers can be placed adjacent if one of them divides the other. Using only $1,...,10$, can you write the longest such list?
You can work out the number someone else is thinking of as follows. Ask a friend to think of any natural number less than 100. Then ask them to tell you the remainders when this number is divided by 3, 5 and by 7...