I thought it would be simple to set-up an addition exercise generator for my
class of young Abacus students. The exercises typically involve adding a
series of numbers (more than two) for a positive result.

The student adds from top to bottom, and should not encounter a negative sum
at any point. To illustrate,
5
-4
-7
8
3


is not acceptable (summing through the third number results in a negative)
but
5
4
-7
8
3

is OK.

I tried to use the RANDBETWEEN() function to generate random numbers for the
problems, but the results are not usable because of this constraint.

I'm hoping for some clever way to ensure that the numbers all line up nicely
so I always get a positive figure at each step of the summation? Negative
numbers do need to be allowed however.

Sriram