Burgers at 89 cents from a 20 dollar bill

Back in $2000$ a burger cost $89$ cents. You pay with a $20 bill and buy as many burgers as possible, ignoring tax. Let $x$ be how many you get and $y$ the change in cents. What is $xy$?

924. $22\times 89=1958$ cents while $23\times89=2047>2000$, so $x=22$ and $y=2000-1958=42$. Then $xy=22\cdot42=924$.