LESSON 5 / 5 · 8 MIN

Basic Operators

LET'S MAKE IT CLICK

Combine your values

Operators combine or compare values. An expression such as 7 + 2 evaluates to a result you can assign or print.

WATCH THE IDEA

Left value7

The first operand.

Operator+

Choose the operation.

Result7 + 2 → 9

Combine the two operands.

An operator connects values to produce a result.

Move through one idea at a time. Watch, experiment, and check your understanding along the way.

Start with arithmetic

WATCH THE IDEA

Add7 + 2 → 9

Find the sum.

Multiply7 * 2 → 14

Find the product.

Divide7 / 2 → 3.5

True division produces a float here.

Different operators answer different questions about the same two values.

Use + for addition, - for subtraction, and * for multiplication. The / operator performs true division: with integers, its result is a float, so 8 / 2 produces 4.0.

See the Python code

print(7 + 2)  # 9
print(7 * 2)  # 14
print(7 / 2)  # 3.5

Whole quotients and remainders

WATCH THE IDEA

True quotient-7 / 2 → -3.5

Start with the exact quotient here.

Round down-3.5 → -4

Move toward negative infinity.

Remainder-7 % 2 → 1

Because -7 = (-4 × 2) + 1.

Floor division rounds down. The remainder keeps the integer division relationship true.

With integer operands, // gives the quotient rounded down, and % gives the remainder. For example, 7 // 2 is 3 and 7 % 2 is 1.

Rounded down means toward negative infinity: -7 // 2 is -4, not -3. Python keeps the relationship a = (a // b) * b + (a % b) for integer operands with a nonzero divisor.

YOUR TURN TO EXPLORE

Change an operator. Inspect the result.

Choose two integers and an operation. Try division by zero or a negative input and watch what Python would display.

Left valueOperatorRight value

example.pyPython

CURRENT VALUESReady

No assignments yet.

OUTPUT

No output yet.

Predict the result, then take the first step.

Enable JavaScript to change inputs and step through this guided example. Here is the initial program and its result:left = 7 right = 2 result = left + right print(result)Expected output:9

Compare values

WATCH THE IDEA

Compare3 == 3

Ask whether the values are equal.

EvaluateEqual values

The comparison is satisfied.

ResultTrue · bool

A comparison returns a boolean.

Use == to compare. A single = assigns a value to a name.

== checks equality; > checks whether the left value is greater. Comparisons produce a boolean: True or False. Remember that = assigns and == compares.

See the Python code

print(3 == 3)  # True
print(3 > 5)   # False

Make the order clear

WATCH THE IDEA

Expression2 + 3 * 4

Multiplication has higher precedence.

Multiply first2 + 12

Evaluate 3 * 4.

Then add14

Finish with 2 + 12.

Parentheses can change the order: (2 + 3) * 4 is 20.

Multiplication and division normally happen before addition and subtraction. Parentheses change the order: 2 + 3 * 4 is 14, while (2 + 3) * 4 is 20.

Division, floor division, and remainder with a zero divisor raise ZeroDivisionError. Check or handle invalid inputs when building real programs.

See the Python code

print(2 + 3 * 4)    # 14
print((2 + 3) * 4)  # 20

TAKE IT WITH YOU

What you have learned

/ and // perform different kinds of division.
Comparisons return True or False.
Parentheses make evaluation order explicit.

Answer both quick checks correctly to mark this lesson complete. You can continue at any time.