Beth needs to add a 10% tip to her $12 meal. how much money does she need to add?

If you would like to know how much money Beth needs to add to her meal, you can calculate this using the following steps:

10% * $12 = 10/100 * 12 = 0.1 * 12 = $1.2

Now, you have to add $12 and $1.2:
$12 + $1.2 = $13.2

Result: Beth needs to add $1.2 (the whole meal will now cost $13.2).