Explain how you can find all the prime numbers from 201 to 1,000

This is a job for a computer.

It does it by brute force. Here are the steps.

for i = 201 to 1000

check if i is even by doing  i mod 2 = 0 then exit this routine. that is if 0 shows up when you do a mod operation on it then leave. The number you are testing is even. Even numbers except 2 are not prime.

next find the square root of i. divide by all the odd number up to that square root.

for j = 3 to sqrt(i) step 2

if i mod j = 0 then exit this subroutine

if you find nothing that divides into i then record the number as prime.j

Try an example

201 is not prime it is divisible by 3

205 is not prime it is divisible by 5

207 is not prime it is divisible by 3

209 well let's see what happens to 209

the square root of 209 is 14

209 is not divisible by 3

209 is not divisible by 5

209 ÷ 7 = 29.85 so 7 does not go into 209 evenly

209 is not divisible by 9. If 3 doesn't work, 9 won't either.

209 ÷ 11 = 19 wwwooops. This number is not prime. 11 divides into it equally.

This method works extremely well for small numbers like 201 to 1000. It is hopeless for much larger numbers.