"Homeschooling with toddlers is a delight, because they have a lot of energy and want to be involved. For those same reasons, homeschooling with toddlers can also be a challenge."
Some ideas you might like to try:
Give them an inexpensive or used workbook to scribble in (and "check" it just as you do with the older kids);
Let them play Cuisenaire® rods, counting bears, or some other math manipulative, or with Legos®;
Give them picture books to look at;
Let them sit on your lap while you read (and point to the pictures or words you are reading to keep them involved);
Have a special school box for use only during school time that includes quiet activities (puzzles, play-dough and cookie cutters, lacing toys, crayons and coloring books, Duplos, etc.);
You might want to offer sensory activities, such as shaving cream in a gallon zip bag to let the children "write" with a finger on it and erase by squishing it around (or use finger-paint);
Have a big Tupperware container filled with rice or beans and let the children use scoops or measuring cups to pour from one container to another;
By about age 2 1/2, children might enjoy albums of nursery rhymes, while looking at board books;
Have your read aloud time with your older students right outside the bathroom door while the children play in the tub;
Put several sheets of paper and a pair of scissors in bag. On each piece of paper, draw one or several lines, some straight, some curved, some zig-zaggy, across the paper in big marker. Put smiley or star at the end. Let them try to cut along the lines;
Create a pile of several small, random things (toys, bottle caps, raisins and peanuts), and allow your children to sort . . . by color, shape, material, size, etc.);
Take 10 index cards and number them 1-10. Glue that many pennies on each card, or draw that many circles on each card. Put pennies, poker chips, etc. in bag, too. They put pennies on card to count up to each number.