When taking a childs temperature under the arm, how many more degrees are you syppose to add to it?

Rule of thumb is one. Add a degree if taking the temperature under the arm, subtract a degree when taking the temperature rectally.
Depends. In our office, we ask that you report the exact number that you got, along with how you took it. Other offices may want you to adjust it on your own. Technically, rectal is the one that's most accurate but if you're using oral as the standard, rectal will usually be higher.