Automatic Calculation

Hi guy,

i created a form of excel that use column A and B, which column A is the name of item (A2 - A10), and B is the price of each item (B2 - B10)
and in B1 is the total of B2 - B10 using =sum(B2:B10), then i did a filter in column A to show me only value in A2- A5 and i expected the total number in B1 is the total number that produce by calculating value from B2 to B5 but the fact is still show me the calculating from B2 to B10, what should i do to achive that goal?

thanks

what is the 9 mean??