Floating-point numbers

A floating-point number is a number with a decimal. Ex: 3.14, or -123.5. float is a data type for floating-point numbers. A floating-point literal is the number being used in your python code. Ex: weight = 145.2

Use scientific notation for huge numbers such as 1.87x1045. Ex: 1.87e45. The e stands for exponent. The value range for floating-point numbers is from 2.3x10-308 to 1.8x10308. range. Assigning a variable outside this range causes an OverflowError. Overflow happens when a value is too large to be stored in the memory allocated by the interpreter.

When printing floating-point numbers, use f string formatting to specify the number of decimals to print out. Ex:

print(f'{math.pi:.3f}')

Arithmetic expressions

Expression: any combination of items such as variables, literals, operators and parenthesis. Ex:

x = 5 * (y + 2). 

In an expression, the right-hand side is evaluated first to get the value, and then assigned to the left-hand side. Literals are actual values in your code. Commas are not allowed in integer literals, so 1,000 is written as 1000

Arithmetic Operators: +, -, *, /, **

Note: ** is exponent (x ** y is x to the power of y)

Compound arithmetic operators

Compound operators are a shorthand way to update the value of a variable

• Addition assignment: +=
• Subtraction assignment -=
• Multiplication assignment: *=
• Division assignment: /=
• Modulo assignment: %=

For example: x = x + 5 is equivalent to x += 5

Division and Modulo operator

For division use the / operator, which returns a floating-point number. For floored division use the // operator, which rounds down the result. Division by 0 is not allowed.

The modulo operator % get the remainder of dividing two integers. Ex: 5%2 is 1. Modulo is useful for finding out if a number is odd or even, by simply doing number %2 and if it returns 0 it’s even, or 1 then its odd. It’s also useful for determining exact change in a vending machine, for example.