Using the conventional units for very small moments in time (nanoSeconds, Picoseconds, etc)
How would you present a period of time that would be described as 1/138000000th of a second?
I would multiply both top and bottom of the fraction by 1000
giving 1000/138 as the main calculation , the result of which will then be followed by x10 to the power of-9
( -9 for the six zeros plus another three zeros because I multiplied by 1000)
just type 1/138000000 into google and the answer is 7.2463768e-9. e-9 = 10 to the power of -9 , the nano prefix = 1 billionth (US) thus 7.25 nano seconds.
The time that would describe as 1/138000000th of a second will be 7.25 nanoseconds. And a nanosecond is equal to 1 billion part of a second or 10−9 second