1. Pascal's calculator (also called the Pascaline): This was Pascal's most famous invention. It was a mechanical calculator that could perform addition, subtraction, multiplication, and division. Pascal invented it in 1642 when he was just 18 years old. The Pascaline was the first mechanical calculator that could be used for all four basic arithmetic operations.

2. Pascal's law: This law states that the pressure applied to a fluid in a closed container is transmitted equally to every point in the fluid. Pascal's law is used in many hydraulic devices, such as hydraulic presses, car brakes, and water fountains.

3. Pascal's triangle: This is a triangular arrangement of numbers that can be used to calculate binomial coefficients. Pascal's triangle is named after Pascal, who first published it in his book "Traité du triangle arithmétique" in 1665.

4. Pascal's wager: This is a philosophical argument for the existence of God. Pascal argues that even if there is only a small chance that God exists, it is still worth betting that he does. Pascal's wager is based on the idea that if God does exist, the benefits of believing in him are infinite, while the costs of not believing in him are relatively small.

In addition to these inventions, Pascal also made significant contributions to many other fields, including physics, mathematics, and philosophy. He is considered one of the most important thinkers of the 17th century.