This is why "assets = liabilities + equity" works much better. You would increase assets by $200, since you got that much cash (cash is an asset). You would in

This is why "assets = liabilities + equity" works much better. You would increase assets by $200, since you got that much cash (cash is an asset). You would increase equity by $200 as well (often accountants will call that "Owner's Equity") since your personal stake in this business (yourself, here) has gone up. That's the double entry.