Okay...
You have the right math, just not the right numbers. :)
https://www.steemnow.com/ (upper right corner is median price of steem in the last 3.5 days) you will notice it here $0.4 because system is a bit messy in the moment. So instead of dividing it with average number (~ $0.25) you'll get the results with division of 0.4.
Hope this helps :)