How do you do this problem

You're on the right track. You found that 18% of $12 is $2.16. This is the amount of the tip only. Add this onto original bill $12 to get 12+2.16 = 14.16, which is the final bill (including tip).

An alternative is to turn 18% into 0.18 and then add 1 to this to get 1.18

When we multiply by 1.18, it will increase the original amount by 18%

So, 1.18*12 = 14.16

i think it might be a but you might want a second opinion