1. ## X:X?

Hi there,

I have never really done sets before and I am trying to understand the notations etc. Any how would I be correct in assuming that where it says x:x is exactly divisible by 3 and x:x is exactly divisible by 7 that it means that its a set that consists of all the numbers in set A that are divisible by 3 , and by 7?

2. The set $\mathcal{C}$ is read “set of all x such that x is exactly divisible by 7”.

3. Originally Posted by Plato
The set $\mathcal{C}$ is read “set of all x such that x is exactly divisible by 7”.
So does that mean that the set of all x is a? And that set C is those in A that divide exactly by 7?

No, the universe is $\mathcal{E}$ not $\mathcal{A}$.