Randy and Ellen live with their three children, Josh (born 2001); Chris (born 2003); and Brad (born 2006). Josh is Ellens child by a previous marriage and she has signed a written agreement allowing her former husband to claim Josh as a dependent. In 2018 line 11 of page 2 of the Form 1040 is $1,558. What amount can they claim as a child tax credit on line 12 of Form 1040?