$cols = 10; //колличство td
$rows = 10; //колличество tr
echo "<table border='1' algin='center'>";
for($tr = 1; $tr <= $rows; $tr++){
    echo "<tr>";
    for($td = 1; $td <= $cols; $td++)
        echo "<td>".$tr*$td."</td>";
    echo "</tr>";
}
echo "</table>";