The total number of slices she gave to Joe and Darcy is 1/2 x 8 = <<1/2*8=4>>4.
The total slice she gave to Carl is 1/4 x 8 = <<1/4*8=2>>2.
Therefore, the total slices left is 8 - 4 - 2 = <<8-4-2=2>>2.
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