"what do you call numbers that cannot be arranged into 2-row arrays? "
(The person who originally posted this question needs to choose an appropriate name to post under. Thanks.)
I believe it's odd numbers since odd numbers are not evenly divisible by 2.
To determine what numbers cannot be arranged into 2-row arrays, you need to consider which numbers are not evenly divisible by 2. These numbers are called odd numbers.
Odd numbers are integers that cannot be divided evenly by 2 and have a remainder of 1 when divided by 2. For example, the numbers 1, 3, 5, 7, and so on, are all odd numbers.
When you arrange numbers into 2-row arrays, you typically pair up each number with another number. Since odd numbers cannot be evenly divided into pairs of 2, they cannot be arranged into 2-row arrays.
Therefore, the answer to your question is that numbers that cannot be arranged into 2-row arrays are called odd numbers.