Arithmetic operators in PHP - Step-by-Step Execution

Concept Flow - Arithmetic operators

Start

↓

Read operands

↓

Choose operator (+, -, *, /, %)

↓

Perform calculation

↓

Store/Display result

↓

End

This flow shows how PHP reads two numbers, applies an arithmetic operator, calculates the result, and then outputs it.

Execution Sample

PHP

<?php
$a = 10;
$b = 3;
$result = $a + $b;
echo $result;
?>

This code adds two numbers and prints the result.

Execution Table

Step	Variable	Value	Operation	Result/Output
1	$a	10	Assign 10	10
2	$b	3	Assign 3	3
3	$result	10 + 3	Add $a and $b	13
4	echo $result	13	Print result	13 printed
5	End	-	-	Program ends

💡 Program ends after printing the result.

Variable Tracker

Variable	Start	After Step 1	After Step 2	After Step 3	Final
$a	undefined	10	10	10	10
$b	undefined	undefined	3	3	3
$result	undefined	undefined	undefined	13	13

Key Moments - 2 Insights

Why does $result hold 13 after step 3?

Because $result is assigned the sum of $a and $b, which are 10 and 3 respectively, as shown in execution_table row 3.

What happens if we try to echo $result before assigning it?

It would cause an error or print nothing because $result is undefined before step 3, as seen in variable_tracker.

Visual Quiz - 3 Questions

Look at the execution_table, what is the value of $b after step 2?

A undefined

B 3

C 10

D 13

💡 Hint

Check the 'Value' column for $b at step 2 in the execution_table.

At which step is the addition operation performed?

A Step 1

B Step 2

C Step 3

D Step 4

💡 Hint

Look for the 'Operation' column mentioning addition in the execution_table.

If $a was changed to 7, what would $result be after step 3?

A 7

B 3

C 10

D 11

E 9

💡 Hint

Recall $result is $a + $b; changing $a to 7 means $result = 7 + 3.

Concept Snapshot

PHP Arithmetic Operators:
- Use +, -, *, /, % to do math.
- Variables hold numbers.
- Example: $result = $a + $b;
- Result can be printed with echo.
- Operators work left to right.

Full Transcript

This example shows how PHP uses arithmetic operators. First, variables $a and $b get values 10 and 3. Then $result adds them with +. Finally, echo prints 13. The flow is: assign values, calculate, print, end. Variables change step by step. Beginners often wonder why $result is 13 or what happens if $result is used before assignment. The quiz checks understanding of variable values and operation steps.