erm.. Well can't be simplified.. so.. I dont really understand the question much. Elaborate more. But, from what you have given me, i have come to this conclusion. This is because if you swim 9 times, every swim session, do you swim 18 lengths each week?
Also, I must point out that there is a flaw in your work. You have stated that prime numbers are the only numbers that cannot be simplified. This is incorrect, for example: (9 is not a prime number, although it cannot be simplified when put over 10)
Another prime number: 5. can be simplified easily even though 5 is a prime number.