The word "teacher" is formed from the verb 'teach' and the person suffix, which is 'or' or 'er' (as in professor, and advisor/adviser).
Yes, you can add the suffix "able" to "teach" to make it "teachable." This turns the word into an adjective meaning capable of being taught.
plus, add, combined
Add is a word.
No, you do not need to add a comma before using the word "plus" when connecting two phrases or clauses. The word "plus" can be used as a conjunction to join two ideas without requiring a comma.
Concetration
If a root word is by itself, you could add a prefix or suffix or add another word to create a compound word. For example, "wordsmith" is formed by combining "word" and "smith" to mean someone who is skilled in working with words, while both "word" and "smith" can stand perfectly well on their own.
add, and, sum, tack on, plus
add, plus, more than, Sum, Mix, combine
It is an exterior angle and an interior angle plus an exterior angle add up to 180 degrees
When you add a suffix to "compete," it changes the meaning or function of the word. For example, adding "ition" creates the word "competition," which refers to the act or process of competing.
sum, add, even the word and mean plus. 2 and 3=5 means 2+3=5
The word 'sum' means you need to add. If you add 1.22 and 2.3 you get 3.52.