I can not solve the equation: 111a-111b+11c-d=8765 using FindInstance:
Thanks.
Try:
FindInstance[1111*a - 111*b + 11*c - d == 8765 && 0 < a < 12 && 0 < b < 12 && 0 < c < 12 && 0 < d < 12, {a, b, c, d}, Integers]