Prints basic multiplication and division, answer is introduced by user.

division-multiplication.php

#!/usr/bin/env php
<?php
declare(strict_types=1);

try {
    assert_options(ASSERT_ACTIVE, true);
    assert_options(ASSERT_BAIL, true);
    main();
} catch (Exception $e) {
    die($e->getMessage());
}

/**
 * Prints basic multiplication and division, answer is introduced by user.
 *
 * Example:
 *
 * ```bash
 * $ ./math.php
 * 49 ÷ 7 = 7
 * 42 ÷ 6 = 7
 * 8 × 2 = 16
 * 6 × 2 = 12
 * 10 × 5 =
 * ```
 *
 * To enable assertion set the following in `php.ini`:
 *
 * ```ini
 * zend.assertions = 1
 * ```
 *
 * @param int $exercises Number of exercises to solve, must be positive
 *
 * @throws \Exception
 */
function main(int $exercises = 20): void
{
    assert($exercises > 0);
    while ($exercises--) {
        $operation = ['÷', '×'][random_int(0, 1)];
        $number1   = random_int(1, 10);
        $number2   = random_int(1, 10);
        $expected  = $number1 * $number2;

        if ('÷' === $operation) {
            $expected = $number1;
            $number1  *= $number2;
        }

        do {
            printf('%s %s %s = ', $number1, $operation, $number2);
            $input = (int)trim(fgets(STDIN));
        } while ($input !== $expected);
    }
}