Seller frank receives an offer of $800,000 on a property he listed at $900,000. how much is the offer as a percent of the listing price? 90.6%? 86.7%? 88.9%? 85.0%?

When you want to find the value of A as a percent of B, you compute
  A/B * 100%
Here, that is
  $800,000/$900,000 * 100% ≈ 88.9%


After you cancel all the zeros, the fraction becomes 8/9, which has a decimal equivalent of 0.8888... [repeating 8s]. Rounded to 3 decimal places, this is 0.889. You can do this one in your head.