Trigger Help. Book value of matched bets.

Whats the easiest way to get the book value of all the matched bets in the market?

hi
b_book
 floating point
 Book percentage formed by the back prices of all selections in the market, for example 89.5, 112.34.
 
l_book
 floating point
 Book percentage formed by the lay prices of all selections in the market, for example 89.5, 112.34.
 
market_volume
 floating point
 Total matched amount in the market given in your currency
 

mcbee

To get the book value of your matched BACK bets you need the match_b_book variable & for matched LAY bets you need the match_l_book variable.
See attached trigger.

Cheers guys for your response. But i have noticed using match_b_book will still change when the back_price changes in the market. But I've figured it out anyway thanks.