What do micro,mega,nano and giga?

Question

prefixes: what do micro,mega,nano and giga mean in terms of numbers?

Answer 1

these are the powers implied in macro & micro world of physics.

micro=10^-6

mega=10^6

nano=10^-9

giga=10^9

Answer 2

micro is millionth (1/1,000,000)

mega is million

nano is billionth (1/1,000,000,000)

giga is billion