Answer :
The key component to remember here is to keep the same significant figures
1) 800,000,000
==> 8 x 100,000,000
==> 8 x 10^8 m
2) 0.0015
==> 1.5 x 0.001
==> 1.5 x 10^-3 kg
1) 800,000,000
==> 8 x 100,000,000
==> 8 x 10^8 m
2) 0.0015
==> 1.5 x 0.001
==> 1.5 x 10^-3 kg