Question

Which are prime 6093 6193 6293 6393 6493 6593 6693 6793 6893 6993? Medal if answered correctly.

Answer 1

you can quickly eliminate some of these by adding the digits to see if they are divisible by 3
the result is 3 6 or 9 if divisible by 3

eg 6093 = 6+9+3 = 18 = 9 so its divisible by 3 so not a prime

Answer 2

6693, 6993 and 6693 also divisible by 3

Answer 3

* 6393 also

Answer 4

neither of them are divisible by 5 because they do not end in 5 or 0
try dividing the others by higher primes like 7 and 11

Answer 5

6193 is divisible by 11 so is not prime

Answer 6

6293 is divisible by 7

Answer 7

use you calculator

Answer 8

you are left with 6493 , 6593 6793 and 6893

Answer 9

kepp dividing by prime numbers in ascending order 7,13,17,19 etc until tou caome to a prime which is higher than square root of the above numbers

I just tried that with 6493 and found its divisible by 43 so thats another one you can eliminate

Answer 10

that leaves you with 6593, 6793 and 6893

Answer 11

try 6593 divided by 19

Answer 12

what do you get?

Answer 13

r u there?