abbreviate
C/o
You can abbreviate it with the letter d. But I can't think of a reason why you wold have to abbreviate the word decimal.
Ca
Master is used without abbreviation.
Sample letter to honor someone
you do not need an abbreviation for a 4 letter word, so there is no abreviation
Just the letter L and for milliliters the letters mL.
necktie
It's a 3 letter 1 syllable word... why do you need to abbreviate it?
i abbreviate it as advs. You could also abbreviate it as adv.
How do you abbreviate challenges