It is time to gain insight into theoretical terms! Let's start.

The first crucial term is **exhaustive events**.

**What is it?**

This term describes when at least one event must happen.

**Example:**

The simplest and the most evident example is tossing a coin. The probability of receiving head or tail is **50%**, but together they result in **100%**(all outcomes). In other words, the events are exclusive. 

Moving on, let us look at another term i.e. **law of total probability**.

To understand better, it is better to solve one task.

**Example:** 

Imagine that we have three boxes. The first one contains **7 red balls**, the second one contains **5 green balls** and the third one contains **4 green balls** and **3 red balls**. Calculate the probability that we will randomly pull out **red ball**.

So, the result is **0.47619048**, to find it we should multiply the probability to pick a specific box by the probability to pull out the box from this column.

It's time to dive deeper into the probability theory. Here we will learn basic formulas. The main idea of the section is to help us to understand the term probability using real-life examples. 

Here, we will get acquainted with the rules in probability theory. This section will be more complicated than the previous one. It will be attractive because we are going to work with the real challenges. But it should be noted that we learn some formulas.

Doing experiments is always funny, but here we will combine exciting tasks with programming learning. In this section, we will work with the binom object to conduct experiments in Python.

Distribution is a key to probability learning, but don't be petrified by this term. This section provides you with real-life explanations and relevant formulas. 

The normal distribution is the most commonly used one. Here we will work with the distribution with the help of real-life challenges.

You have two baskets the first one contains 3 cats' toys and 7 dog's (10 toys), the second one contains 6 cat's toys and 14 dog's (20 toys). The probability to choose one of the basket is 50% or 0.5. Calculate the probability to get cats' toy. Place items in the correct order.