Operator precedence and evaluation in PHP - Interactive Code Practice

Practice - 5 Tasks

1fill in blank

easy

Complete the code to add 2 and 3, then multiply the result by 4.

PHP

<?php
$result = (2 + 3) [1] 4;
echo $result;
?>

Drag options to blanks, or click blank then click option'

A*

B/

C-

D+

Attempts:

3 left

💡 Hint

Common Mistakes

Using + instead of * causes the result to be 5 + 4 = 9, which is incorrect.

Forgetting parentheses changes the order of operations.

The multiplication operator (*) has higher precedence than addition, but parentheses force addition first. So (2 + 3) * 4 equals 20.

2fill in blank

medium

Complete the code to check if 5 is greater than 3 and less than 10.

PHP

<?php
if (5 [1] 3 && 5 < 10) {
    echo 'True';
} else {
    echo 'False';
}
?>

Drag options to blanks, or click blank then click option'

A!=

B>

C==

D<

Attempts:

3 left

💡 Hint

Common Mistakes

Using '<' instead of '>' reverses the comparison and gives false.

Using '==' checks equality, not greater than.

The expression 5 > 3 checks if 5 is greater than 3, which is true. Combined with 5 < 10, the whole condition is true.

3fill in blank

hard

Fix the error in the expression to correctly calculate 10 minus 3 times 2.

PHP

<?php
$result = 10 - 3 [1] 2;
echo $result;
?>

Drag options to blanks, or click blank then click option'

A+

B/

C-

D*

Attempts:

3 left

💡 Hint

Common Mistakes

Using '+' instead of '*' changes the result incorrectly.

Using '-' again causes wrong calculation.

Multiplication (*) has higher precedence than subtraction (-), so 3 * 2 is calculated first, then subtracted from 10, resulting in 4.

4fill in blank

hard

Fill both blanks to create an array with keys as numbers and values as their squares, but only for numbers less than 5.

PHP

<?php
$squares = [];
for ($i = 1; $i <= 6; $i++) if ($i < 5) $squares[[1]] = [2];
print_r($squares);
?>

Drag options to blanks, or click blank then click option'

A$i

B$i * $i

C$i + $i

D$i - 1

Attempts:

3 left

💡 Hint

Common Mistakes

Using addition instead of multiplication for squares.

Using wrong keys that don't match the numbers.

The key is the number $i, and the value is its square $i * $i. The condition limits to numbers less than 5.

5fill in blank

hard

Fill all three blanks to create an associative array with uppercase keys, values as numbers, and only include values greater than 2.

PHP

<?php
$numbers = [1, 2, 3, 4];
$result = [];
foreach ($numbers as [3]) if ([2] > 2) $result[[1]] = [2];
print_r($result);
?>

Drag options to blanks, or click blank then click option'

Astrtoupper($num)

B$num

D$number

Attempts:

3 left

💡 Hint

Common Mistakes

Using different variable names inconsistently.

Not converting keys to uppercase.

The key is the uppercase string of the number (strtoupper($num)), the value is the number itself ($num), and the loop variable is $num. The condition filters values greater than 2.