The number in the top-right corner of the screen is the current real-time total value of your account.
(1) the current value of your investments (see: what is the current value of my investment?).
(2) the amount of total Cash remaining in your portfolio, including your Ring Fenced amount (see: what is my total amount of Cash?)
If you have any further questions in regards to this, please feel free to contact us via email at BUX Support.