'; echo "123" + 1; echo '
'; echo "123" + "1"; echo '

'; // Arithmetic operators. echo 'Arithmetic operators
'; echo 'Addition (+) ' . 1 + 2 . '
'; echo 'Subtraction (-) ' . 2 - 1 . '
'; echo 'Multiplication (*) ' . 2 * 2 . '
'; echo 'Division (/) ' . 4 / 2 . '
'; echo 'Modulus (%) ' . 4 % 2 . '
'; $a = 1; $a++; echo 'Increment (++) ' . $a . '
'; $a--; echo 'Decrement (--) ' . $a . '
'; echo '
'; // Assignment operators. echo 'Assignment operators
'; $a = 2; echo $a . '
'; $a += 2; echo $a . '
'; $a -= 2; echo $a . '
'; $a *= 2; echo $a . '
'; $a /= 2; echo $a . '
'; echo '
'; // Comparison operators. echo 'Comparison operators
'; $a = 1; $b = 2; $c = '2'; echo ($a < $b) . '
'; echo ($a > $b) . '
'; echo ($a == $b) . '
'; echo ($a != $b) . '
'; echo ($b == $c) . '
'; echo ($b === $c) . '
'; echo '
'; // Formatting numbers. echo 'Formatting numbers
'; echo 'Round (2.49): ' . round(2.49) . '
'; echo 'Number Format (21233122):' . number_format(21233122) . '
'; echo 'Printf: '; $sub = 5; $tax = 0.65; printf('The subtotal is %u, making the tax %.2f.', $sub, $tax); echo '
'; echo 'Mt Rand: ' . mt_rand(0, 100);