Worksheets? Yikes!
Being gifted doesn't mean a love of "schooly" stuff. It's an aptitude for learning-- which often is likelier exemplified by asking incessant questions, a reputation as the most legalistic four-year-old on the block (or the planet), or dismantling the TV/dresser/baby locks (possibly to see how they work, possibly to get parts for his planned World Domination Robot).
Yep.
We never used flashcards or gave worksheets to our kids because we believed it would actually have the effect of loss of interest for learning and schoolly stuff. Each started school with high expectations then quickly learned how mundane the worksheet/multiple choice test early elementary curriculum really is.
We did not want them to know that fact in advance.