the superlative degree of much is most

Teach is a verb and so has no superlative form.

smallest. you add est when you want to make it a superlative.

A superlative is a word with a suffix that implies that it is of the greatest magnitude or quality relative to its form without the suffix. An example of a sentence with the word "superlative" is "The superlative of 'tall' is 'tallest. '"

The superlative degree of word sincere can be most sincere ,or sincerest according to its use in the sentence.