Need a ruling

[Barbarian Horde]

Someone has illusion of gold or any other coin in a pile. Any illusion spell other then shadow was used to cast this.

Then If another player uses "Easy Math" spell. Would they realize that it was an illusion, or would the "easy math" spell count the gold in the illusion.

Easy math can be found in (Song and Silence: A Guidebook to Bards and Rogues)

[Gildedragon]

Seeing how easy math is an estimate, the coin passes.

[BowStreetRunner]

Since the target of the spell is you, it is not going to matter that the coins are an illusion. You'll get an estimate of the number of illusory coins without any additional information revealing them to be an illusion.

[MisterKaws]

You're not interacting, so no.