Is your daughter frustrated by fractions? Is your son puzzled by percentages? If so, count your family among the millions who may have math phobia — now listed as a psychological disorder by the American Psychiatric Association.

Many of us think math phobia is more common among girls than boys. But a University of North Carolina study of test scores shows that it may strike both genders almost equally. “The largest gender difference [we saw] between boys and girls was late in high school, and that was only 1.5 percent,” says lead author Erin Leahey.

Experts have linked low math test scores to such factors as:

• Diets low in iron (a special concern for girls starting to have periods). Too little iron can cause anemia, harming development of the thought process.
• Too much reliance on calculators.
• Problems with short-term memory.

A study by Cleveland State University psychologists found math anxiety feeds on itself. “Our results certainly suggest that spending mental time worrying about your anxiety is exactly what disrupts working memory and performance,” says co-author Mark Ashcraft, Ph.D. “The anxiety reaction is causing the problem, not some deep-seated deficiency at math.”

Make It Add Up What can parents do to help head off math phobia? Teach your child that math isn’t just a system of obscure skills they must master through drills and memorization. It’s a way to make sense of relationships — between parts and wholes, shapes and sizes, or beginnings and endings. It helps us find patterns in the way the world works. Show children math’s role in daily life. “Let them hear you figure out the time you need to leave to get to the movies on time,” says educator Marilyn Burns, author of Math: Facing an American Phobia. Focus on grasping concepts. Educators say that’s just as critical as finding the right answer. “Real math is messy,” Ms. Burns says. “Anyone who works with budgeting, for example, is dealing with uncertainty and variability.” Don’t hand down a poor attitude toward math. It won’t help to say, “I was never any good at math either.” Instead, say, “Let’s look at that together.”