MYSQL/Laravel LIKE behaving unexpected

I have ha bunch of mathematical tasks which I want to filter through a textbox.

For example: 4*1 should return 4*1, 4*10, 4*11, ... 4*11 should return 4*11

To do that I wrote this piece of code:

$operator = DB::connection()->getPdo()->quote("{$operator}");
$operand2 = DB::connection()->getPdo()->quote("{$operand2}%");
DB::table('tasks')
        ->select(DB::raw('*'))
        ->whereRaw("operand1 = {$operand1} AND operator = {$operator} AND CAST(operand2 AS CHAR(50)) LIKE {$operand2}")
        ->get();

The results of this are pretty unexpected und unpredictable.
When I type 4*5 I get 4*{any operand}
When I type 4*12 I get 4*1, 4*10, 4*11, 4*12

via Chebli Mohamed