Teams account for child without phone number

I am trying to set up teams accounts for my 2 kids since we all will need different logins between my work and their school.  I was able to create the account, get a verification email to the child's email address, but when I try to finish setting up the account, it requires a phone number.  My children do not have phones and it will not let me use my phone number again.  How do I set it up without requiring another phone number?