Who to include in your taxable household
Your household includes the tax filer, the spouse, and the tax dependents.
A dependent is a person other than the taxpayer or spouse who lets the taxpayer to claim a dependency exemption. Each dependency exemption decreases income subject to tax by the exemption amount. A dependent decreases the amount of the taxpayer’s taxable income, which saves them money.
If a child is living with parents while going to school then the child is considered a dependent of the parents and you can include this person into your taxable household.
However, if the child is living with the parents and the child files their taxes, the parents can no longer claim the child as a dependent.