what do you call the numbers that cannot be arranged into 2-row arrays?
The numbers that cannot be arranged into 2-row arrays are called prime numbers. Prime numbers are positive integers greater than 1 that have no divisors other than 1 and themselves. To determine if a number is prime or not, you can follow these steps:
1. Choose a positive integer greater than 1.
2. Check if the number is divisible by any positive integer from 2 to the square root of the number. If it is, then it is not a prime number. If it is not divisible by any of these integers, then it is a prime number.
For example, let's take the number 7:
1. Check if 7 is divisible by any positive integer from 2 to the square root of 7 (approximately 2.65). 7 is not divisible by 2, 3, 4, 5, or 6.
2. Since 7 is not divisible by any of these integers, it is a prime number.
Therefore, 7 is a number that cannot be arranged into 2-row arrays.