first work out the expression and then correct the answer to 4 s.f = 241.34..............(A) (3 x 10-3)2............(B) = 32x2 = 1103 x 1103 (Note that x2 = 1x3) = 24.34 x 32 x 1106 = 2172.06106 = 0.00217206 = 0.002172(4 s.f)