Company A owns the following investments:
trading securities (fair value) 60,000
available for sale securities (fair value) 35,000
held to maturity securities (amortized value) 47,000

Do I add the 35,000 and the 47,000 to get 82,000?

Add it for what purpose?

I assumed they were both investments.

Is this the correct assumption?

All three are investments. Trading securities are current. The other two can be current or long-term. I know you titled the thread long-term, but since trading securities aren't long-term, I really didn't know if that was relevant to your question or not. If they are long-term and you want to total them together, then yes. You weren't very clear about exactly what you were trying to accomplish.