1/5.1/2.1/5.1/10.1/16

1/5 × 1/2 × 1/5 × 1/10 × 1/16
= 1/80 × 1/10 × 1/10
= 1/8 × 1/1000
= 125/1000 × 1/1000
= 125 × 10^-6
= 1,25 × 10^-4