Euler found four whole numbers such that the sum of any two of the numbers is a perfect square...
The diagram illustrates the formula: 1 + 3 + 5 + ... + (2n - 1) = n² Use the diagram to show that any odd number is the difference of two squares.
How much peel does an apple have?
A plastic funnel is used to pour liquids through narrow apertures.
Have you ever tried pouring a drink from a glass back into a bottle ?
You don't need a specified volume, but it may help to ask what proportion cone would hold a litre of liquid using the least amount of plastic.
See the Hint for more help.