The most important lessons to learn at home right now are the concrete ones. Don't even look for worksheets - there's nothing that can be learned from them that can't be learned more successfully with objects. I suggest you have these things in your home:
-an egg carton
-good quality art supplies : crayons, block crayons, paint, scissors, Ferby pencils, hole punchers, different papers, pipe cleaners, and stamps.
-pretend play items: food, dolls, etc.
-"real" play items: a stethoscope, flashlights, cookware, cleaning supplies, cheap camera. The difference from pretend play is this stuff all works. It adds an extra dimension to their pretend and gives you tools to continue on learning later.
-sand/box of rice
-pasta or beans
-tweezers, toast tongs, children's chopsticks
-puzzles, the kind where each piece is the shape it should be (ex. a bird puzzle would have the shapes of the wing, beak, foot, body, tail, head as pieces, South America would have each country its own piece).
You probably have a lot of this, right? Set up low work stations, either defined by a sheet on the floor or find a coffee table at a yard sale. You can work on so many different skills with just a few basic items, and get a LOT more out of the learning experience than worksheets would offer.
I mean...okay, we're working on area/volume in math right now. I introduced Euler's law through the Sir Cumference books, and we spent yesterday building polyhedra out of toothpicks and gumdrops, building boxes and finding surface area then volume, finding the perimeter of different objects, including where Rectangle the Donkey walked all over our Cathedral board (first found the perimeter, then found how much area he ruined that we'd have to "replace".
With a 3yo, start with the basics - teach handwriting in the sand, washing up after lunch (going counterclockwise circles), sorting with the toast tongs, allowing freedom with the Ferby (triangular) colored pencils. Teach math with sorting different objects, playing hopscotch, putting wikicircles around groups, candyland and Hi Ho Cherry-O. Science is experiments around the house and museum time, social studies is being in the world, pre-reading skills come from drawing pictures, being allowed to play with letters, you reading to her, even library books that have no/few words, like The Red Book or the Carl series.
There are a TON of things you can do with a 3yo that's not "schoolish", but education and learning. I love this site here - www.besthomeschooling.org
- there's plenty of ideas and links under its preschool and K activities list that are fun to do.