The Book of Mormon and the Old Testament are similar regarding number usage.
Biblical Hebrew employs cardinal numbers (one, two, three), ordinals (first, second, third), multiplicatives (double, sevenfold,) and fractions (half, third, tenth), avoiding complex numeric forms (those using mono-, bi-, di-, uni-, tri-, multi-, and poly-). Book of Mormon language follows this pattern as well.
Furthermore, in Hebrew, numbers are often used without the noun in constructions that seem to be missing something when translated into English. For example, Genesis 45:22 says that Joseph “gave three hundred of silver” to Benjamin, not qualifying exactly what the three hundred referred to. The King James translators added the word “pieces” to make the phrase sound more correct in English. In the Book of Mormon, the statement that Laban “can command fifty, yea, even he can slay fifty” (1 Nephi 3:31) does not specify what fifty refers to. As we read in Echoes and Evidences, fifty might refer to men, warriors, princes, or commanders of armies. Other Book of Mormon examples of this Hebrew usage pattern are found in 2 Nephi 11:3, Alma 57:19, and Alma 57:25.
In Hebrew, it is common practice to connect two or more numbers with “and.” An example is found in 1 Kings 20:1, where we see “thirty and two kings” rather than “thirty-two kings.” The Book of Mormon follows this usage pattern, as in “an army of forty and two thousand” (Mormon 2:9). (See Echoes, 174–175.)