The Missing Number

"The Missing Number" is a logical game.

You must deduce the number in a 6 series numbers.

You can choose from 3 difficulty levels: easy, medium and hard mode.

Each level consists in a series of 6 numbers and you must deduce the 4th number in that series.

How to play:
- Tap on the "?" sign to display a Numerical KeyPad;
- Tap the number (maximum 5 characters) and press Done (the KeyPad will disappear);
- Tap on Validate Button; if is the correct answer you will pass to the next level;

Rules:
1. You can try 4 times, but if the 5th try is still wrong, the gave is over!
2. Points:
a. Easy Mode
i. Succeeded from 1st try - 20p;
ii. Succeeded from 2nd try - 8p;
iii. Succeeded from 3rd try - 6p;
iv. Succeeded from 4th try - 3p;
v. Succeeded from 5th try - 1p;
b. Medium Mode
i. Succeeded from 1st try - 100p;
ii. Succeeded from 2nd try - 40p;
iii. Succeeded from 3rd try - 30p;
iv. Succeeded from 4th try - 15p;
v. Succeeded from 5th try - 5p;
c. Hard Mode
i. Succeeded from 1st try - 200p;
ii. Succeeded from 2nd try - 80p;
iii. Succeeded from 3rd try - 60p;
iv. Succeeded from 4th try - 30p;
v. Succeeded from 5th try - 10p;

Here are some example formulas:

1. A series of prime numbers, starting with 2: 2, 3, 5, 7, 11, 13;
2. Powers of 2 (2^1, 2^2, 2^3, 2^4, 2^5, 2^6): 2, 4, 8, 16, 32, 64;

You are welcome to send us some new series for the next versions.

Have fun!