A supercomputer can do 136.8 terra calculations per second. How many calculations can it do in a microsecond

"terra ... " as a prefix means 10¹²,

so the unit speed of this computer is

136.8 x 10¹² calcs/sec.

"micro ... " as a prefix means 10⁻⁶,

so in that amount of time, the computer can do

(136.8 x 10¹² calc/sec) x (1 x 10⁻⁶ sec) = 136.8 x 10⁶ calcs.

That's ...

... 136.8 mega-calcs

... 0.1368 giga-calcs

... 136,800 kilo-calcs

... 136,800,000 calculations