## Question

Why does is_prime fail for some numbers?

## Answer

If your code is failing for some numbers, it’s likely because you’re `return`

ing too soon, or because you’re `return`

ing the wrong thing in the wrong place. Without giving away the answer, take a look at the example control flow pseudo code below:

```
# From hint: any number less than 2 is not prime
if x is less than 2:
return x is not prime
# This loop is where we put our number to the test and return False
# so the function exits immediately if x isn’t prime
for n from 2 to x:
if x is evenly divisible by n:
return x is not prime
# If we made it here, our number must be prime because none
# of the other return statements were executed!
return x is prime
```