# Concise notes and tutorials for continuous learning.

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#### Fundamental principle of counting

The Fundamental principle of counting (or Multiplication principle) states that: "If an event can…

#### Arrangement without repetition

Given a set of different objects, how may distinct arrangements of the objects are there? For…

#### Arrangement allowing repetition

Given a set of different items, how may distinct arrangements of items are possible, provided any…

#### Pythagoras' theorem

The Pythagoras' theorem (or Pythagorean theorem) states that: "In a right-angled triangle, the…