Rounding with Signifcant digits?

Question

carry out the indicated operation and give your answer with the specfied number of significant digits?

Question1) 45 x 32.1;5 significant digits

Answer 1

45.000 x 32.000 = 1440.0 5 significant digits
40 x 30 = 1000 to 1 significant digits
(or if you prefer)
4.5x10^1 x 3.2x10^1 = 1.440 x 10^3 rounded to 1 digit is 1.0 x 10^3