Numbers 3:39

All that were numbered of the Levites, which Moses and Aaron,
numbered at the commandment of the Lord, throughout their families,
&c.] Whence it appears, that Moses was not alone, but Aaron with him, in numbering the Levites, and that by the appointment of the Lord. The word "Aaron", in the Hebrew text, has a dot on every letter, for what reason it is not certain; the word itself is left out in the Samaritan and Syriac versions:

all the males, from a month old and upward, [were] twenty and two
thousand;
22,000 men; but by putting the sums together they amount to three hundred more; for of the Gershonites there were 7,500, and of the Kohathites 8,600, and of the Merarites 6,200, in all 22,300; which difficulty some endeavour to remove by saying, as Aben Ezra observes, that the Scripture takes a short way, mentioning the thousands, and leaving out the hundreds but this, he says, is not right, nor is it the way of the Scripture in this chapter: and in an after account of the firstborn of the Israelites, not only the hundreds are mentioned, but the broken number of seventy three. Others think there is a corruption crept into the text somewhere in the particular numbers, through the inadvertency of some copyist; and suppose it to be in the number of the Kohathites, where they fancy (vv) , six, is put instead of (vlv) , three: but there is no occasion to suppose either of these, for which there is no foundation, since the reason why three hundred are left out in the sum total may be, because there were so many firstborn among the Levites, and these could not be exchanged for the firstborn of the other tribes; they, as such, being the Lord's, and one firstborn could not redeem another; and so it is said in the Talmud {t}, these three hundred were firstborn, and there is no firstborn redeems a firstborn, or frees from the redemption price of five shekels.