Magic Sphere?

"I'm fed up with rectangular objects.. Do you have some magic triangle, circle, or sphere?" Yep! At least there is one deserving the name magic sphere. Look at the following diagram. There are 6 intersection points between the three big circle. Try to fill 1..6 in them to make every circle sums up to the same number! It may looks a bit difficult at first, but in fact, once you start filling, you're nearly done.

Ummm... What about using your mathematical mind to calculate the 'magic sum' first? Click on the sphere to see the solution.

To be continued ...