Getting units of a two-digit number

To get the unit, just calculate the rest of the division by 10:

$num = 25;
echo $num % 10; // Imprime 5

And for the decade, just take the whole part of the division by 10:

$num = 25;
echo intdiv($num, 10); // Imprime 2

The same works for negative values:

$num = -25;
echo intdiv($num, 10) . PHP_EOL; // Imprime -2
echo $num % 10 . PHP_EOL; // Imprime -5

See working at Ideone .

PHP 5

Since the intdiv function was only introduced in PHP version 7, an alternative to PHP 5 is to use the round function:

echo round($num/10, 0, PHP_ROUND_HALF_DOWN);

The first value refers to the value to be rounded; the second refers to the number of decimal places and the third if the same should be rounded down. This would return 2 for $num = 25 and -2 for $num = -25 .

In the php all string can be considered an array of characters and it is possible to cast an int to string, so you can get the digits of a number like

In PHP 7

$num = 25;
$dig1 = ((string)abs($num))[0];
$dig2 = ((string)abs($num))[1];

In PHP > = 5.4

$num = 25;
$dig1 = strval(abs($num))[0];
$dig2 = strval(abs($num))[1];

Divide by 10 and take the rest of the division.

$num = 25;
$unidades = 25 % 10; // retorna 5

You can use the php str_split () function

$array = str_split($num);