# Doodle Digits - How to play

## General

The task of the uDigits game is to cross out all digits on the field
in as few moves as possible. Cross the digits by finding pairs
of matching digits in certain locations on the field. The
match occurs when the two digits are **the same**
or if their **sum is 10**. For example, you can cross
out digits 3 and 3 (they are the same, equal) or you can cross out
3 and 7 (the sum of those numbers is 10).

However, even though the two digits are the same or their sum
is 10, the match can occur only if they are in
**certain locations** on the field. But where
exactly, depends on the selected skill level.

## Skill levels

There are 3 skill levels in the game: Beginner, Advanced, and Pro. The easier level you select, the more rules you have at your disposal, with each rule determining the location of the pair of digits that you can cross on the field. Let's start with the most challenging level that has a single rule, and then add one additional rule to each "easier" level.

### Pro:

When playing the game as a Pro, only one basic rule applies:

1. You can cross out two digits that are **next to each
other** horizontally (they follow one another, either on
the same row or wrapping to the next row), or vertically.

Note: already crossed out digits do not count, therefore the
two matching digits can be in absolutely any position on the
field if all digits **between them** are already
crossed out.

### Advanced:

When playing the game at an Advanced level, one additional rule makes it easier to cross out the digits:

2. You can cross out the two digits that are the **first
uncrossed and the last uncrossed** digits on the field.

### Beginner:

When playing the game as a Beginner (the easiest level), another additional rule helps you to faster cross out all the digits:

3. The two matching digits can be located **diagonally**,
but only on **consecutive rows**, for
example the first digit on one row and the second digit on the
row directly under it.

Applying the rules mentioned above, your task is to cross out all the digits on the field. When you cannot find any matching digits, select Add Digits (designated by the Plus symbol) to add more digits to the field, and continue crossing them out, until you clear the entire field.

## Game types

The game is available in 3 types: Classic, Modern, and Random.
The selected type of the game determines the **initial set**
of digits on the field and also the digits that **get added**
when you select Add Digits.

### Classic:

In Classic games, the initial set of digits are
**numbers from 1 to 19**, and when you cannot find
any more matching digits, all digits that were **not crossed
out** are copied as new digits when you select Add Digits.

### Modern:

In Modern games, the initial set of digits has **random**
values when the game starts, however when you cannot find any
more matching digits, and decide to add more, then just
like in a Classic game, all digits that were **not crossed out**
are copied as new digits.

### Random:

In Random games every new digit gets a **random**
value when the game starts. And every time you choose to Add Digits,
every newly added digit also has a totally **random value**.

## Playing the game

Start crossing out pairs of digits on the field, applying the
rules described above. Every row that you cross out (all 9 digits
on a row) will disappear to clear up space. When you feel like
there are no more valid moves, **select Add Digits**;
it is not done automatically — you decide when to add more
digits manually.

### Winning the game:

You win the game when you **clear the entire field**
— when no digits are left at all. The less digits you crossed to clear
the field and therefore the **smaller your score** is — the
higher you get ranked (so try to **keep your score as low as possible**).

### Losing the game:

There is a limit to a number of digits on the field — you
cannot have more than three thousand (**3000**) digits
on a field at any given time. If you Add Digits and the total number of
digits on the field becomes more than three thousands — you
lose the game. If adding more digits might result in losing the game —
the plus symbol and the score will highlight in orange color as a warning.

### Bonuses:

In Beginner and Advanced skill level (not Pro), after each
set of 100 crossed digits you get a bonus — an opportunity
to cross out a digit of **any** value, but only located
in a position that is valid according to the rules of the selected
Skill Level. You may collect bonuses and use them at a later time.
However, every time you use a bonus, you get penalized with +20
score points, which increases your score, while the objective of
the game is to keep your score as low as possible.

## Enjoy!

We believe we did our best to keep the spirit of the game alive in this digital version, the same way it is played on a paper with a pen or pencil. We hope you enjoy playing the game as much as we enjoyed creating it. Have fun!