While I don't consider myself a hardcore gamer, I do tend to get quickly addicted to casual math games. Give me a set of numbers, some form of logic problem to solve in a few seconds or more, and I can start round after round, often resulting in hours of continuous play. I have tried dozens of math games for Android and kept finding myself drawn toward the most minimalistic ones. Below is a list of ten such games, with simple designs that don't detract your focus away from the riddles.

### Countdown Maths Game Pro

Countdown Maths Game is the quintessential math game. If you have ever seen the cult French TV show Des Chiffres Et Des Lettres or the British equivalent Countdown, the rules and objective should be very familiar to you. You are given six different numbers and a target total. Your goal is to add, multiply, subtract, or divide those six numbers to get to that result. It sounds deceptively simple until you get 3, 4, 6, 7, 9, and 10 to make 314, and you have to do [4*6*(10+3)]+(9-7) to reach it. And that isn't even on the Hard level.

Countdown Maths Game has multiple difficulties starting from Uber Easy and going all the way to Mental. And if you want to challenge a friend's math skills, there's a two player mode where each of you gets the same question to solve in a set period of time. Further options include customizations of the time limit, color schemes, and default mode settings.

Compared to the free version, the Pro adds two game modes that challenge you to complete a given number of questions faster, or more questions in a specified time. Another interesting Pro advantage is the option to save a question for later. I find myself often using that to come back to the head-scratchers that eluded me in order to solve them with a fresh pair of eyes.

### Math Effect

Math Effect takes an almost opposite approach to math problems. Both the equation and its solution are laid out in front of you, and you only have to choose whether that result is correct or false. Sometimes, the question is very easy, such as, 2+1=3, but you will also see more advanced problems, like 95*5=465. Speed is of the essence here as well as unwavering accuracy. Make one mistake, and the game is over.

This requirement of perfection adds pressure and difficulty to Math Effect. It's ridiculous how often your hand reaches for that Yes button before your brain is able to tell it that it should have been a No. "I can do better," you tell yourself before starting another game. It helps that every round lasts just a few seconds, unless you're playing the unlimited game, and that the graphics and animations keep the equations rolling in front of you smoothly and beautifully.

Math Effect has a time mode, a fixed equation one, and an unlimited mode with five seconds for every equation. The more you solve and score in any of these, the higher your level and rank are. A detailed statistics page keeps a tab on your efficiency and best results, and connects to Google Play Games for Leaderboards and Achievements. For now, the score to beat is 3.35 seconds for solving 10 questions. My personal best is above 10 seconds. I guess I have some work to do…

### Quento

Quento gives you a 3x3 board consisting of five numbers and four operators. Start with a number, swipe to an operator, and then back to another number in order to obtain the total asked by the game and earn a star.

There are three stars to collect in four difficulty levels that differ by how many numbers are required to get the total. Collect all stars and you can move to another board. It's straightforward enough that any kid or adult should be able to play and enjoy it.

There are no settings (only a mute button), no various board sizes, no rankings, no levels, and none of the extras that usually entice gamers. Yet, when my friend pointed me to Quento, I installed it, put my head down, and didn't raise it for another three hours. I was instantly convinced by the game's simplicity and efficiency. With one set of numbers, you have to solve 12 different problems, and that is both remarkable and challenging.

### Threes

I couldn't possibly list number games without mentioning the one that you must have recently read and heard about the most. Threes marries beautiful design, appealing colors, adorable characters, simple gameplay, and addictiveness into one exploding mixture that makes you spend hours on end trying to chase a better score.

The game's math is simple: combine 1 and 2 to get 3, 3 and 3 for a 6, 6 and 6 for a 12, and so on with multiples of threes. You do that by sliding all the numbers on the 4x4 board in the same direction. If two numbers can overlap to make a combination, you clear up a slot. But each slide you make also introduces a new number to the board. Your goal is to get the highest possible numbers on the board before it fills up and you can't make a move.

And fill up it will. Threes is a constant march toward this inevitability, but the challenge of the game relies in how long you wave that off, how far ahead you plan your moves, and how smart you are at making several combinations with a single swipe to clear the board as much as possible.

### Nove: Number Swipe

While Nove is the least challenging game of this selection, it has its place as the kind of distraction you need during those moments when you are bored but don't want to rack your brain. Essentially, it is more about visual acuity and short-term planning than mathematical prowess.

A 5x7 grid of colored numbers is shown, and you have to swipe across adjacent (even diagonal) and similarly colored numbers, but always in an ascending order. Switching colors is possible between tiles with the same number. The longer your swiped sequence, the higher your score. The game is played either in a Zen Mode that has no time limit, or a Challenge Mode where you only have a minute to get the highest possible score.

### Balls on my screen

Balls On My Screen is Dots with an added layer of difficulty. Balls (or dots) carry a number and can only be connected in a sequence equal to it: one 1, two 2s, three 3s, and so on. New balls replace the old ones, and the game keeps going. The Arcade Mode is the most challenging, forcing you to go faster between connected balls to get more time. Take a breath, and the clock catches you.

Balls On My Screen becomes frustrating when you have a sequence of five 6s but no sixth one to complete it. That's where the +1 and -1 options come in handy. Drag them to any ball, and they will change its value accordingly. You'll have to use them sparsely though, as they can unblock the game when you have no moves left but will also cost toward your final score.

### 2Vars

Building on a math equation with two missing variables, 2Vars is an easy to understand but difficult to master game. Only one number of the equation is given to you, and you should select the two variables between two sets of multiple options. Sure, the equation looks obvious once you have found the answer, but those few seconds you spend looking for it feel long and frustrating.

There are time constraints for each riddle and rising difficulties as you solve and level up. Make a mistake, and you lose a life. Do that three times and the game is over. But 2Vars' appeal and strength is in its unpredictability. You never know which form of equation you will get next, or which operator will be used. As you progress, the math becomes harder and harder to solve, with advanced divisions and multiplications that confuse you.

2Vars also makes use of Play Games' Leaderboards and Achievements. I'm still trying to figure out how to get the Flash achievement, which requires solving a riddle in under a second!

### 10

Slide blocks around to combine them and form a total of 10. That's the whole premise of the game, but don't let its simple mechanics fool you. 10 is ruthless and mind-bending, addictive and tricky. 300 levels are available, and each one is solvable, albeit with a lot of trial and error.

Once you realize that you can easily walk yourself into a corner where your remaining blocks are either trapped or combine into totals higher than 10 (for example, 6, 6, and 8), you will start planning in advance and replaying levels until you find their solution.

10 also exists in a 9 (Free) version where you can test your solving skills in 45 different puzzles.

### Simply Sudoku

Sudoku games are a dime a dozen on the Play Store, but Simply Sudoku is the one I have kept installed on my Nexus 7. That is mainly due to the way the game is designed and played. Both the typography and animations are beautiful, adding a layer of joy that you might have lost after playing sudoku for years.

As with many other sudoku games, Simply Sudoku comes with preset and random puzzles, various difficulty levels, hints, and a pencil mode. However, it offers many unique advantages as well, like a smart keyboard that only shows the possible numbers when you highlight an empty cell. Another bonus is obtained by long-clicking on the pencil, which fills all the cells with their possible solutions.

Simply Sudoku doesn't reinvent the wheel when it comes to sudoku, it simply enhances it. Still, if you're a hardcore fan, you can disable all of the game's assistances but still enjoy its gorgeously clean looks.