Oh ok, well for this case they don't seem suitable as you're not allowed to use semicolons in conditions:
if(0.34 < computerChoice;computerChoice < 0.66;)
will only give you syntax errors. You'll later learn about && and || which help you chain conditions
A && B is true when both A and B are true and false otherwise and
A || B is true if at least one A or B is true.
Where A and B could be anything that evaluates to a boolean value so e.g.
0.34 < computerChoice && computerChoice < 0.66
would be possible.
BUT you don't need them in this exercise. Because due the the borders of Math.random you already made sure that the range is from 0 to 0.3. if you ask if it is below 0.33 and as the first case already checked this interval. A check for below 0.66 is suitable to ensure that a value is in 0.33 to 0.66 aso.