PROD on WP 34S on DM 42

[Didier Lachieze]

Instead of providing the range in X and Y you need to provide in X a loop control number in the format cccccc.fffii : at each run cccccc is decremented by ii until cccccc is less than fff. If ii=0 cccccc is decremented by 1.

In your example for SUM you have 100 in X : cccccc=100, fff=0 and ii=0, so SUM is doing the sum of your function from 100 to 0. Adding 0 at the end doesn’t change the sum, but for PROD, multiplying by 0 at the end returns 0.

You should use 69.001 as the starting value in X for PROD.