Challenge Level

If a two digit number has its digits reversed and the smaller of the two numbers is subtracted from the larger, prove the difference can never be prime.

Challenge Level

A composite number is one that is neither prime nor 1. Show that 10201 is composite in any base.

Challenge Level

A 2-Digit number is squared. When this 2-digit number is reversed and squared, the difference between the squares is also a square. What is the 2-digit number?

Challenge Level

Can you explain the surprising results Jo found when she calculated the difference between square numbers?

Challenge Level

Which armies can be arranged in hollow square fighting formations?

Challenge Level

There are unexpected discoveries to be made about square numbers...

Challenge Level

Choose four consecutive whole numbers. Multiply the first and last numbers together. Multiply the middle pair together. What do you notice?

Challenge Level

Can you find out what is special about the dimensions of rectangles you can make with squares, sticks and units?

Challenge Level

Find the largest integer which divides every member of the following sequence: 1^5-1, 2^5-2, 3^5-3, ... n^5-n.

Challenge Level

Many numbers can be expressed as the difference of two perfect squares. What do you notice about the numbers you CANNOT make?

Challenge Level

Explore what happens when you draw graphs of quadratic equations with coefficients based on a geometric sequence.

Challenge Level

What is special about the difference between squares of numbers adjacent to multiples of three?

Challenge Level

If you know the perimeter of a right angled triangle, what can you say about the area?

Challenge Level

The sums of the squares of three related numbers is also a perfect square - can you explain why?

Challenge Level

A mother wants to share a sum of money by giving each of her children in turn a lump sum plus a fraction of the remainder. How can she do this in order to share the money out equally?

Challenge Level

Can you find the hidden factors which multiply together to produce each quadratic expression?

Challenge Level

Can you produce convincing arguments that a selection of statements about numbers are true?

Challenge Level

Take any prime number greater than 3 , square it and subtract one. Working on the building blocks will help you to explain what is special about your results.

Challenge Level

Given any 3 digit number you can use the given digits and name another number which is divisible by 37 (e.g. given 628 you say 628371 is divisible by 37 because you know that 6+3 = 2+7 = 8+1 = 9). . . .

Challenge Level

Show that if you add 1 to the product of four consecutive numbers the answer is ALWAYS a perfect square.

Challenge Level

a) A four digit number (in base 10) aabb is a perfect square. Discuss ways of systematically finding this number. (b) Prove that 11^{10}-1 is divisible by 100.

Challenge Level

Two cubes, each with integral side lengths, have a combined volume equal to the total of the lengths of their edges. How big are the cubes? [If you find a result by 'trial and error' you'll need to. . . .

Challenge Level

Find all the triples of numbers a, b, c such that each one of them plus the product of the other two is always 2.

Challenge Level

Take a triangular number, multiply it by 8 and add 1. What is special about your answer? Can you prove it?