Some say mental arithmetic is a dying art, and they may have a point. Take a trip to any major store when the tills are down, for instance, and you’ll see just how incompetent the average human being is without a computer doing the leg work for them. Numbl, however, just might be the ticket to get our brains back in gear, its simple number-based play helping to get the blood flowing up top.

Its concept is an especially simple one. You’re presented with twenty numbers at the bottom of the screen and a target number at the top. It’s your job to use those twenty to reach the target figure as quick as you can. Addition is the only method here, so combining the numbers available to you in quick time is the key.

Alternatively, if the number you’re seeking is already amongst the twenty at your disposal, then you can simply plump for that rather than having to reach the total through a combination.

Success, however, stems from your ability to use as many numbers as you possibly can. For instance, if your target is 9, it’s far better to use 2+3+4 than it is 8+1. That’s because once each number has been used, it’s removed from the board altogether, the level coming to an end once all twenty have been ticked off. The more numbers you use up, the less targets are thrown your way.

Numbl

As you might expect, Numbl’s controls are far from complex. Your only input is to tap the numbers you wish to use, the game flashing red if the combination you try simply doesn’t add up. Each move you make is also beautifully met by a series of crisp sounds, the game avoiding an unnecessary soundtrack but keeping play alive by making sure your inputs aren’t met by total silence.

But it’s perhaps Numbl’s two player mode that most impresses. When activated, it turns the iPhone’s screen from its default portrait standing to landscape mode, each player facing the other and taking charge of one half of the screen.

Play is naturally scaled down to accommodate this set-up, but the aim remains the same. Instead of twenty numbers, each player takes charge of just nine, the aim of clearing the board as quick as possible naturally remaining.

While the games themselves can be over in the blink of an eye (a quick check of the worldwide single -player leaderboard shows the quickest completion time to be just 4.565 seconds), in multiplayer the games are served up as part of a wider contest, each victory adding a point to a running scoreboard.

As such, Numbl is the kind of title that lends itself to repeated play with a friend on a long journey, but also serves up the perfect solo stop gap for those spare five minutes in the day.

In truth, it’s really hard to find fault with Numbl, its one downside perhaps the fact that it’s a simple number puzzle and nothing more. But for those looking for such a challenge, Numbl will more than likely get their juices – and indeed fingers – flowing with ease, its simple yet engaging play ensuring that one quick run at totting up those digits is rarely enough.