Enter T or F depending on whether the statement is true or not. (You must enter T or F -- True and False will not work.) If it is true do a proof and if it is false provide a counter-example (Of course the proofs and counter-examples must be written down on paper!). 1. The difference of 2 even numbers is even. 2. The product of 2 rational numbers is rational. 3. If a is divisible by 3 then a is divisible by 9. 4. All even numbers are prime. 5. If a is divisible by 2 then a is divisible by 4. 6. If a is divisible by 4 then a is divisible by 2.