Trading is related to Money. Money is related to Spending. Coin can be used for Spending. Change is a type of Coin. 
Board is a type of Fare. Board is related to Written. 
Trading <--RelatedTo--> Money <--RelatedTo--> Spending <--UsedFor-- Coin <--IsA-- Change 
Fare <--IsA-- Board <--RelatedTo--> Written 