In case you genuinely aren't kidding then what that (1 - 10*B2) means
is that the formula:
(1) takes value from cell B2
(2) multiplies the value by 10
(3) subtracts the multiplication [B2*10] from 1 thus
one minus (ten multiplied by value in B2)


What I wouldn't be too sure about, however, is whether in your
particular instance you need the circular reference - i.e., you're
saying that you've got the formula in Cell B2 but at the same time the
formula takes value from the same cell (B2)... Although, there are
valid scenarios for Circular references but that's you're call if
yours is the one.
Not sure if i helped.