Answer :
I think that poor boy Tim has enough pieces(1/3, 1/4, 1/6, 1/12) and does not need to cut anything.
1/3 + 1/6=4/12 + 2/12=6/12=2/4
1/4 + 1/12=3/12 + 1/12= 4/12= 1/3 or 1/4
1/3 + 1/6=4/12 + 2/12=6/12=2/4
1/4 + 1/12=3/12 + 1/12= 4/12= 1/3 or 1/4