Question

2. Suppose the national debt is $80 trillion and the government spends $800 billion during the fiscal year on goods and services. In addition, the government collects tax revenues of $600 billion and makes transfer payments equal to $300 billion. Assume the economy is producing at the potential or full employment output level. The budget balance for this economy is equal to $________ billion and the national debt is $ _________ trillion.

600-800-300=-500 Billion this is the budget balance, I can't figure out how to get the national debt. I thought it was 80 trillion but it is not, please help!