Question

Is 37 composite or prime?

Answer 1

Prime

Explanation:

Aside from memorizing this, we can calculate the fact that it is prime.

For a number to be composite, it must be the product of two numbers (other than itself and one). Let's do some multiplication!

`2xx18=36`
`2xx19=38` - not divisible by 2

`3xx12=36`
`3xx13=39` - not divisible by 3

`color(red)(5xx7)=35`
`5xx8=40` - not divisible by 5

`color(red)(7xx5)=35`
`7xx6=42` - not divisible by 7

And here we can stop. As the left number continues to increase further (11, 13, 17, etc), the right number will already have been found to not be divisible into 37. And so 37 is prime.