were you married to his father at the end of 2018? did you live together during the last 6 months of 2018? who did the child live with if you lived apart?
Qualifying child
1) Related - ok
2) Same principal abode as taxpayer for more than ½ the tax year. Temporary absences like for school are ignored
3) If not a full-time student, under 19 at the end of the tax year. If a full-time student under 24 at end of tax year.
Full -time means an individual who during each of 5 calendar months during the calendar year in which the taxable year of the taxpayer begins is a full-time student at an educational organization described in section 170(b)(1)(A)(ii), or is pursuing a full-time course of institutional on-farm training under the supervision of an accredited agent of an educational organization described in or of a State or political subdivision of a State.
4) Hasn’t provided over ½ his/her own support
if you are married at the end of 2018 and spouses did not live apart for the last 6 months of 2018 you could only file a joint or married filing separate (MFS) return
if married and lived apart or not married, then if you paid more than 1/2 the cost of keeping up the home for you and your child who lived with you for more than 6 months you can file as head of household otherwise a joint or MFS return
if you weren't married on 12/31/2018 and did not pay more than 1/2 the cost of keeping up the home for you and your child who lived with you for more than 6 months you can only file as single
