I've been trying to figure out a solution to this problem as well, as I have a 7, 4, and 1 year old. Here's what I've come up with so far. When we start work, the 2 older children do independent review work that I know they can do on their own, while I play with the 1 year old. When older are done, 4 year old takes a break and plays with the baby, while I do 1 on 1 with the 7 year old. When 7 yr old needs a break, she plays with the baby, while I do 1 on 1 with the 4 year old. Switch again so 7 year old gets an extra session. In the afternoon, when baby is sleeping we do the science experiments, history, etc so baby can't destroy it! So far so good... :)