Inserting things like °, °C, ¾, ¼

Hi,
I am translating a recipe book, and things like °, °C, ¾, ¼ are repeated often. I tried to insert those as a term, but TB doesn't recognize them nor the Autosuggest. What I do for now is Ctrl+Insert, so I get the thing (°C, ¾, ¼) on the target fragment, then I change the rest of the fragement. I already tried Advance/Insert symbol, but there are so many (and so similar) that I fear I will insert a wrong symbol (e.g. °, º, ˚).

I would like to know how could I do to easily insert those things, so I can increase my productivity.

Any suggestions?