Brittany has 3 gerbils: Puffy, Muffy, and Scruffy. Puffy weighs 5 ounces more than Muffy. Muffy weighs 3 ounces less than Scruffy.  If Scruffy weighs 12 ounces, how much would the scale indicate, in ounces, if Brittany put Puffy and Muffy on the scale?
Muffy weighs 12 - 3 = <T>subtract(12, 3)=9 ounces
Puffy weighs 5 + 9 = <T>add(5, 9)=14 ounces.
If Brittany weighs both Puffy and Muffy, the scale would read 9 + 14 = <T>add(9, 14)=23 ounces
