Understanding Core
Arithmetic Operators

What are Arithmetic Operators?

Arithmetic operators are used to perform mathematical operations like addition, subtraction, multiplication, and division. They form the building blocks of any numerical computation in programming.

List of Common Arithmetic Operators

• + : Addition
• - : Subtraction
• * : Multiplication
• / : Division
• % : Modulo (Remainder)

Example 1: Basic Arithmetic Operations

Let’s take two numbers and apply all the arithmetic operators to understand their behavior.

START
  SET a = 10
  SET b = 3

  PRINT "Addition: " + (a + b)
  PRINT "Subtraction: " + (a - b)
  PRINT "Multiplication: " + (a * b)
  PRINT "Division: " + (a / b)
  PRINT "Modulo: " + (a % b)
END

Output:

Addition: 13
Subtraction: 7
Multiplication: 30
Division: 3
Modulo: 1

Question: Why does division of 10 by 3 give 3 instead of 3.33?

Answer: In many programming environments, when both operands are whole numbers (integers), the division operation returns only the integer part (i.e., floor division). This is called integer division. If decimal accuracy is needed, you must explicitly convert operands to a floating-point type.

Example 2: Working with Negative Numbers

Let’s see how subtraction and modulo behave with negative numbers.

START
  SET x = -15
  SET y = 4

  PRINT "Subtraction: " + (x - y)
  PRINT "Modulo: " + (x % y)
END

Output:

Subtraction: -19
Modulo: -3

Question: Why is -15 % 4 equal to -3?

Answer: In some languages or environments, the modulo operation keeps the sign of the dividend (first number). Hence, -15 % 4 gives -3. Always check how your programming language implements modulo.

Example 3: Using Arithmetic Operators to Swap Values

Can you swap two numbers without using a temporary variable?

START
  SET a = 5
  SET b = 7

  a = a + b   // a becomes 12
  b = a - b   // b becomes 5
  a = a - b   // a becomes 7

  PRINT a, b
END

Output:

a = 7, b = 5

Why does this trick work?

Answer: This works due to the reversible nature of addition and subtraction. By using these operators carefully, you can store and recover both original values without any extra space.

Example 4: Applying Arithmetic in Real Life

Let’s calculate the average of 3 scores:

START
  SET math = 80
  SET science = 90
  SET english = 85

  SET total = math + science + english
  SET average = total / 3

  PRINT "Total: " + total
  PRINT "Average: " + average
END

Output:

Total: 255
Average: 85

Key Takeaways

• Arithmetic operators are fundamental to all mathematical computations.
• Division between integers may discard the decimal part.
• Modulo is useful for checking divisibility, wrapping around values (like in clocks), and more.
• Be aware of operator behavior with negative numbers—it varies by implementation.