The grammarians wrote that for a number less than ten, the noun with it will be counted in plural, and for a number greater than ten, the noun with it will be counted in singular.

And after investigation, I saw that although with a number less than ten their words are correct, with a number greater than ten, their rule is not credible. And we find: שנה שנים (year, years), איש אנשים (man, men), אמה אמות (mother, mothers).

And according to the sages of blessed memory, there was a rule for this, that in all of the Scripture, whenever something is counted (with a number greater than ten) in singular – it teaches that all of the things that are counted are similar to one another.