How to get original values from cumulative sum values?

I have a list of cumulative sum values. I want to obtain another list with the values that generated the cumulative sum vaues. Something like a reverse cumulative sum process. I tried (X2-X1) formula for each consecutive value but couldn't get the exact values. Can someone please help me to reverse the cumulative sum values to original values.

Thank you

Answer 1

[Stephen23]

X = rand(1,9)

X = 1×9

0.8615 0.8710 0.7907 0.5073 0.3673 0.4523 0.4018 0.2258 0.1596

Y = cumsum(X)

Y = 1×9

0.8615 1.7326 2.5233 3.0306 3.3979 3.8502 4.2520 4.4778 4.6374

Z = [Y(1),diff(Y)]

Z = 1×9

0.8615 0.8710 0.7907 0.5073 0.3673 0.4523 0.4018 0.2258 0.1596

max(X-Z) % alomsot zero

ans = 4.4409e-16

Because of the accumulated floating point error getting exactly the same values is not expected.