To cut a rectangular sheet of metal into 8 pieces requires only 7 cuts, where each cut is the width of the sheet. If each piece needs to be half the width of the sheet then only 4 cuts are required: one cut down the length dividing it into two equal halfs and three cuts across further dividing it into quarters.
If the sheet is circular then 4 cuts would suffice to cut it into 8 segments by cutting 4 diameters.
A table could be used to show the time elapsed for making the cuts: one column would show the number of the cut, 1 to 8, and another column the time taken to make the cut. A third column could show the accumulated time to make a cut together with all the cuts preceding it. For example, the second and third columns for cut #1 would be the same and would just be the time to make the cut. The second column for cut #2 would have the time taken to make the cut and the third column would be the sum of the third column for cut #1 and the second column for cut #2. Similarly, for cut #3, its third column would be the sum of #2's third column and #3's second column. And so on for each cut until all 8 pieces had been cut.