pls help quick with sig figs hw...?

Question

I know nothing and professor wont help.

45.6/ 2.4=

12.57-6.2=

(754+0.8)/1.3=

(49.53 x 1.20) + 12=

also:

the density of osmium is reported by one source to be 22610 kg/m^3. What is the density in g/cm^3? What is the mass of a block of osmium measuring 10.0 cm X 8.0cm X 9.0 cm?

Answer 1

45.6/2.4 = 19 (the answer is 2 sig. figs).

12.57 - 6.2 = 6.37 (the answer is 3 sig. figs)

(754 + 0.8)/1.3 = 580.6153846 (answer is 9 sig. figs).
This can be shortened to say 580.6 (4 sig. figs).

71.436 (5 sig. figs).

22610 kg/m^3 = 22610000 g/m^3 (x 1000 g = 1 kg)
22610000 g/m^3 = 22.610 g/cm^3 (divide 1000000cm^3 = 1 m^3)
Vol = 10 x 8 x 9 = 720 cm^3
Therefore mass = 720cm^3 x 22.610 g/cm^3 = 16279.2 g
or 16279.2 g = 16.2791 kg.