Plz help me i beg of u?

828. all there is to it!

here, if you ever need with rounding (or other forms of arithmetic/math) again, use this:

thats the rounding one, but if you just click the top left, it shows you all the calculators you may need!

use this formula:

p(a\b) = p(a and b)/p(b).

take it from here.