## Force on the bottom of a swimming pool

I don't understand WHY my Webassign says I have this wrong. Here is the problem:

" What are the total force and the absolute pressure on the bottom of a swimming pool 2.6 m by 1.6 m whose uniform depth is 2.0 m?"

My book says the force = density X Area X depth below the surface X g

so f = (1X10^3) X (2.6 X 1.6) X (2) X (9.8) = 81536...with 3 sig figs 81500. Tried entering both 81500 N and -81500 N and both were wrong. It seems straightforward so what did I do wrong? Thanks!
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 Recognitions: Science Advisor Perhaps becuase the question asked for two quantities? It asks for both absolute pressure and total force. Also, I get 81619 N when I run the numbers. Perhaps that may be the issue as well.
 Yea, there are two slots in my Webassign, Im looking for the force first and then absolute pressure. Sorry I should have clarified that. you got 81619? I keep getting 81536..am I missing a number??

Recognitions: