The value of a given carry, when adding modulo p
(The Proof of (19))
(19)
Proof:
Given integers n and m, we take r=n-m.
Define
if there is a `carry' in the jth digit when we add m and r in base p; otherwise let
(including
).
We observed, in the proof of Kummer's Theorem that, for each integer
,
Therefore, if we let
be the least residues, in absolute
value, of
, respectively, so that
times the
left side of (19), plus
equals n-m-r = 0. However,

and (19) follows.