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Operators: do math in your code

Code can do math for you. With +, -, and *, your program adds up a hero's power, doubles a score, or works out anything you need.

The big idea

An operator like + or * takes two numbers and gives you a new one.

See it in code

1Start simple

Code can do math for you. The + operator takes two numbers and gives back a new one:

python
hearts = 2 + 1
print(hearts)
Run it — the code adds the numbers:
3

2 + 1 became 3, and we stored it in hearts. An operator's job is to turn numbers into a new number.

2A step further

The * operator means multiply — computers use * instead of a × sign. Here it doubles a number:

python
coins = 5
doubled = coins * 2
print(doubled)
Run it — the number doubles:
10

5 * 2 made 10. Swap the 2 for a bigger number to triple or quadruple instead.

3In our world

Our hero has some strength and some magic. Total power is just the two added together. We use + to add, then * to double it for a boost:

python
strength = 12
magic = 8

power = strength + magic
print("Total power:", power)

boost = power * 2
print("With a boost:", boost)
Run it — the code does the math:
Total power: 20
With a boost: 40

12 + 8 made 20, and 20 * 2 made 40. The * means multiply — computers use * instead of the × sign.

The same idea, everywhere

Math operators run under the hood of everything. A game adds points, art multiplies a position to space stars out, a money app subtracts a cost. Once you can add and multiply in code, you can compute anything.

Try it yourself

Give the hero armor: make a box armor = 5 and add it to power. Then try - to spend 10 power on a spell, and print what is left.

The common mistake

Using x for times. In code, 2 x 3 is an error — the multiply sign is the star *. Write 2 * 3 to get 6.

What it unlocks

Numbers you compute get compared with comparison operators and stored in variables to use again later.

Older, or want more depth? Read the Teens version →

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