you can claim grandchild as a qualifying child if all these tests are met
• has the same principal abode as you for more than ½ the tax year. Temporary absences like for school are ignored
• if not a full-time student, under 19 at the end of the tax year. If a full-time student, under 24 at the end of the tax year.
• hasn't provided over ½ own support
• didn't file a joint return unless there was no tax liability but merely filing jointly to facilitate refund of taxes withheld or estimates paid
or you can claim the grandchild as a qualifying relative if all these tests are met
• gross income for 2020 less than $4,300
• you provided over ½ support
• isn't a qualifying child of another taxpayer
