9000mm
because there is ten mm in one cm
I would say 32, just from doing PEMDAS.
SOLUTIONS
Solve a given equations or algebraic symbols?

(A)

(B)

(C)

(D)
Open the compass it is more than half of the distance between a and b, and scribes arcs of the same radius centered at a and b. call the two points where these two arcs meet c and d. Draw the line between c and d. CD it is the perpendicular bisector of the line segment AB. call the point where CD intersects AB and E