If total assets increased by $10,000 and total liabilities decreased by $6,000, then stockholders equity changed by what amount and direction during the period?

1. increased by 4000

2. decreased by 16,000

3. Did not change

4. increased by 16,000

I know the answer is #4 but can you please explain I am a little confused as to why this is the answer. I would really like to know how to solve this. thank you.