My childrens accounts are linked to mine. We all share my email. How do they login in to thier individual accounts?

I'd like my children to be able to earn badges and track their own progress but we all share my email so when I log in It looks like Elizabeth (that's me) is doing first-grade math, high school math, etc. In other words there is no distinct tracking for the different users on the account. While in theory, Khan Academy says that my children don't need their own email accounts it appears they actually would need to because I have gone through the process of trying to add a child (to start over) and then I say that "my child does not have an email" but at the login page - the next page I'm shown-when I enter the child's user name and my password it will not let me log in. Does my child have a different password than me on the same account?? I wouldn't think this would be so difficult. I wish Khan academy would make it easy for my kids to just log in to their lessons from my account with my email. Thanks for any advice. I'm not sure there is good answer besides just creating email accounts for my little ones-even though that seems a little weird. Thanks, Lizzy