You may also like

problem icon

14 Divisors

What is the smallest number with exactly 14 divisors?

problem icon

Summing Consecutive Numbers

Many numbers can be expressed as the sum of two or more consecutive integers. For example, 15=7+8 and 10=1+2+3+4. Can you say which numbers can be expressed in this way?

problem icon

Dozens

Do you know a quick way to check if a number is a multiple of two? How about three, four or six?

Funny Factorisation

Stage: 3 Challenge Level: Challenge Level:3 Challenge Level:3 Challenge Level:3

Some 4 digit numbers can be written as the product of a 3 digit number and a 2 digit number using the digits $1$ to $9$ each once and only once.

The number $4396$ can be written as just such a product. Can you find the factors?

Maths is full of surprises! The number $5796$ can be written as a product like this in two DIFFERENT ways, and so can the number $5346$. Can you find these four funny factorisations?

Here is another puzzle, again you must use the digits $1$ to $9$ once, but only once, to replace the stars and complete this multiplication example.

* * $9$
$4$ *
--- --- --- ---
* $6$ * *

This gives altogether six funny factorisations and there is one more. You might like to write a computer program to find all seven funny factorisations or you might come up with a different method. Let us know.