3 ms·
Yes, a simple consequence of e.g. 3-digit number being: 100x + 10y + z modulo 3 Removing 9y and 99x gives equivalence: x + y + z modulo 3 Now what’s left is
by DmitryOlshansky 6y ago
Yes, a simple consequence of e.g. 3-digit number being:
100x + 10y + z modulo 3
Removing 9y and 99x gives equivalence:
x + y + z modulo 3
Now what’s left is induction with proper base (1-digit).
- red_admiral 6y agoAs dan-robertson mentioned in another branch, you don't even need induction - you can sidestep it by writing X = sum_i x_i 10^i and noticing that all the 10^i are 1 modulo 9 (and therefore modulo 3).