Maryland Worksheet A — Child SupporObligationio— - Primary Physical Custody is a form used to calculate the amount of child support due from a non-custodial parent to a custodial parent in the state of Maryland. This worksheet is used for cases of primary physical custody, meaning the custodial parent has physical custody of the child more than 50% of the time. This worksheet is used in conjunction with the Maryland Child Support Guidelines and factors in the number of children, parents' combined income, childcare expenses, health insurance costs, and any applicable credits. There are two versions of Maryland Worksheet A — Child SupporObligationio— - Primary Physical Custody: one for parents who have a combined income of $25,000 or less and one for parents who have a combined income of more than $25,000.