2nd try, same message - syntax errors fixed. I'm new to maple and just made a discover. In fact I'm an older adult, getting back into math and realizing how much I've forgotten. Anyhow, I'm wondering if I'm looking at this correctly. The following: sum(piecewise(n < 8, 0, n), n = 0 .. 7) produces 0 While the following: sum(piecewise(n < 1, 0, n), n = 0 .. 7) produces 28 For some reason I was under the impression, that the results above would be reversed, my thinking being that the summation would start with 0 and work it's way forward rather than beginning at the end and working backwards which it appears to be doing to produce the results shown above. Tim