Riddles, brain puzzles and mathematical problems

[BAndrew]

Fun fact:

1 + 2 + 3 + 4 +5 ... = -1/12

The sum of all positive numbers up to infinity, is equal to -1/12.

Not exactly...

The sum of all the positive numbers does not converge. It is divergent series. However, in specialized mathematical contexts, values can be usefully assigned to certain series whose sequence of partial sums diverges. A summability method or summation method is a partial function from the set of sequences of partial sums of series to values.