I have 110 gold and 56 silver when i try to make a purchase for 100 silver the message says that I don't have enough money.

Could anyone advise please

Apologies if i I am missing the obvious i'm new to the game

Thank you in advance

There is no conversion from silver to gold, or vice versa. The rate of exchange fluctuates based on user demand, especially for the items in the premium shop. 

When you are purchasing an item the system does not convert the currencies. You don't have 100 silver, so you can't buy anything for 100 silver. I suggest you play around in explore and find some silver. You can make the difference up quickly :)

Let me know if I am being unclear. ^^

There are no silly questions, let me know if you have more!

Thank you for your help