You may notice that the gender of the cardinal numbers seems backwards from three onward. No, this is not a mistake in the paradigm. Indeed most cardinal numbers in the masculine form look feminine and vice versa. (Don’t bother asking why—that’s just the way it is!)
In addition, while adjectives, unlike English, normally come after the nouns they describe (עַם־רָב vs. “a numerous people”), numbers come before the nouns they modify. That is, all except for the number one—אֶחָד—which behaves like a normal Hebrew adjective. Hence, one man is written אִישׁ־אֶחָד whereas two men reads שְׁנֵי־אֲנָשִׁים. You may also note from this example that the ם is dropped from the word שְׁנַיִם the same as it would in construct form. This is something special about the number two.