Workbooks at 3? Really? If a child would turn up at my house (I'm a childminder) with worksheets at that age I think I'd throw them away (the sheets, not the child). They need to play, make mud pies, build castles, draw, learn to make friends, learn to take turn, listen to stories and make up stories, climb, skip, jump, cut with scissors, put their shoes on on their own.
My DS is gifted in maths and much older (he is now in year 6) and I would have never, ever done worksheets with him. Identify numbers on car number plates, houses, count steps, count up in two, count up (and down) in three whilst playing Janga, do puzzles, put toys in categories (by size, colour, use), measure and weigh teddy bears, bake and measure/weigh the ingredients, play 'bulls eye' and add up the results, etc. There are hundreds of ways that you can do maths with a toddler without worksheets.