The calculator is a wonderful modern electronic instrument designed to make the tasks of adding, subtracting, dividing and multiplying less taxing for the arithmetically retarded.

Originally available with just four buttons and powered by a small colony of ants, today's devices often have more dials, switches and levers than a futuristic robot, and are able to draw their power from sunlight.

In this way, you might liken calculators to plant life: growing sums instead of petals.

However, if you did this, you would be an idiot, as the two are clearly completely different.

The most irritating feature on a calculator is obviously when a solar powered calculator is built without an 'off' button - to shut it down, it must be sealed in a dark dungeon, or drawer!

That is very irritating.