There are **9** NRICH Mathematical resources connected to **Difference of two squares**, you may find related items under Algebraic expressions, equations and formulae.

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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.

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

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

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The diagram illustrates the formula: 1 + 3 + 5 + ... + (2n - 1) = nÂ² Use the diagram to show that any odd number is the difference of two squares.

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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?

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Which armies can be arranged in hollow square fighting formations?

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By proving these particular identities, prove the existence of general cases.

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Take any pair of two digit numbers x=ab and y=cd where, without loss of generality, ab > cd . Form two 4 digit numbers r=abcd and s=cdab and calculate: {r^2 - s^2} /{x^2 - y^2}.

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Euler found four whole numbers such that the sum of any two of the numbers is a perfect square...