Similar to the numbers game on UK TV's Countdown, your goal is to calculate a target figure given six numbers and the four basic arithmetic operators (+ − × ÷). Meanwhile, the clock is ticking down to zero.

Quickfire allows you to choose the level of difficulty and the available time, so the puzzles range from easy to fiendish. Whether you want to practice your times tables, or simply exercise your brain, there is a level for you.

This addictive game makes you think about numbers and can quickly help to build speed and confidence in mental arithmetic.

As well as being a great game to play on your own, you can also play against your friends. The multiplayer mode allows you to compete head-to-head with another player, both working on the same puzzle at the same time. The winner is the first to get there, or the one who gets the closest.

Your recent average time to complete the puzzles is calculated for you, and can be uploaded to the Game Center Leaderboard to see how you compare with the rest of the world.

You can break your calculation down into a number of small steps. If you use a mix of operators at any stage, the game correctly applies multiplication and division before addition or subtraction (BIDMAS) and automatically inserts brackets to clarify.