%timeit runs the command (or Jupy. Noteb. cell) many times
In [1]: %timeit sum(range(100000))
100 loops, best of 3: 2.91 ms per loop
%time runs the command/cell one time AND displays the result
%time sum(range(100000))
CPU times: user 2.68 ms, sys: 3 µs, total: 2.68 ms
Wall time: 2.69 ms
>>> 4999950000