Learn C++/

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Do Some Math

Do Some Math

Use +, -, *, /, % to do basic math in C++.

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In this lesson, you’ll use C++ as a calculator. You’ll write simple math operations, see the results instantly, and learn how to combine numbers in code.

Goal

You’ll aim to:

  • Use arithmetic operators.

  • Perform addition, subtraction, multiplication, division, and modulo.

  • Display results using cout.

Your first calculation

Here is a C++ program that performs addition and prints the result on the screen.

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#include <iostream>
using namespace std;
int main() {
    cout << 5 + 3 << endl; // Adds 5 and 3, then prints the result (8) and moves to a new line
    return 0;
}

Simple addition—your C++ program does the math and prints it.

Try all the operators

Just like addition, C++ can perform all the basic arithmetic operations.

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#include <iostream>
using namespace std;
int main() {
    cout << 5 + 3 << endl; // Addition
    cout << 10 - 4 << endl; // Subtraction
    cout << 6 * 7 << endl;  // Multiplication
    cout << 20 / 5 << endl; // Division
    cout << 10 % 3 << endl; // Modulo (remainder)
    return 0;
}

Below are the five basic arithmetic operators, along with their syntax and results.

Arithmetic Operators

Operator

Description

Syntax

for 7 and 4

Results

for 7 and 4

+

Addition: Adds two operands

7 + 4

11

-

Subtraction: Subtracts two operands

7 - 4

3

*

Multiplication: Multiplies two operands

7 * 4

28

/

Integer division: Divides the first operand by the second and gives an integer quotient because both operands are integers

7 / 4

1

%

Modulo: Returns the remainder when the first operand is divided by the second

7 % 4

3

You’ve used all five basic arithmetic operators.

Mini challenge

Write a program that calculates the result of:

  • Your age*12 (months)

  • Number of weeks in a year (52*7)

  • The remainder of 17 divided by 4

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#include <iostream>
using namespace std;
int main() {
  // Your code goes here
  return 0;
}

If you’re stuck, click the “Show Solution” button.

Tips

  • Integer division in C++ drops any decimals.

  • % only works with integers.

  • You can mix math and text in a single cout.

What’s next?

You’ve calculated. Next up, store those values in variables—and reuse them like pros.