①ヤマをかける:guess what will be on an exam ②ヤマを外されちゃった(ヤマをはずした): The contents of the test was not what I studied. You have guessed wrong. ③一枚も二枚も上手: My teacher is a cut above the rest!

First of all, thank you very much for your help. It did me help see the structure more clearly. Again thank you very much for your help! :)

Let me translate this very casual conversation into more normal Japanese. Perhaps then you can tell what they are saying: A: テストにヤマをかけたら、まったく外されてしまったのだよ。. . . B: それは、先生の方が一枚も二枚も上手（うわて）ということだよ。... There are two idioms. 1. (試験に)　ヤマをかける。...... 2. 一枚上手（いちまい うわて）。