Brooks Company purchases debt investments as trading securities at a cost of $$66,000$ on December $27.$ This and only purchase of such securities$.$ At December $31,$ these securities had a fair value of $$72,000.$

Brooks sells a portion of its trading securities $($costing $$3,000)$ for $$4,000$ cash. Analyze each transaction above by sh on the accounting equation$-$specifically, identify the accounts and amounts $($including $+$ or $-)$ for each transaction.