timer

Reports a number representing the time elapsed since the program started, or since the last resett command was run. The number is in tenths of a second. See resett.

Example: 

resett

Wait a little.

show timer
22

The next procedure displays a question just after resetting the timer. If you got the right answer, it tells you how fast you were at typing it. The value of the timer is divided by ten in order to get the value in seconds. 

to reflex
resett
question [What is 12 times 12?]
ifelse answer = 144 
  [announce se timer / 10 "sec]
  [announce [Wrong answer]]
end