"Thinks" is Third-person singular simple present indicative form of the verb "think"
I think, he thinks, they think (Present Simple). I am thinking, he is thinking, they are thinking (Present Continuous).
The third form of "wait" is "waited."
The third form of the English word "receive" is "received".
The third form of the word "split" is "split." In English grammar, there is usually not a separate form for the third form, as it remains the same as the base form.
The third form of shine is shone.
"Thinks" is the third-person form of "to think", which is a verb... so no, it is not a plural noun.
The third person form of arrive is "arrives."
The third form of shrink(i.e. to minimize something in size or miniature things) is Shrunk
"Thinks" is Third-person singular simple present indicative form of the verb "think"
One third in decimal form is .3333 repeated
One third is already in it's simplest form.