A study which tested the numerical ability of couples found that those with higher scores stood a greater chance of earning more wealth than those whose scores were low.
Researchers found that when both spouses answered three numeracy-related questions correctly, family wealth averaged 1.7 million dollars, while among couples where neither spouse answered any questions correctly the average household wealth was 200,000 pounds.
Numeracy is the ability to reason with numbers and other mathematical concepts, and are skills typically learned during school.
"We examined several cognitive skills and found that a simple test that checks a person's numeracy skills was a good predictor of who would be a better family financial decision maker," said James P. Smith, of the Labor Markets and Demographic Studies at the RAND Corporation, a nonprofit research organization.
Researchers found that choosing the wrong person as a family's primary financial decision maker can have consequences.
While families choose the less-numerate spouse less than 20 percent of the time, when this does happen total household wealth is lower.
Researchers said the skills needed to make successful investment choices are among the most cognitively demanding that a family has to make, especially as they get older and assume greater control of decisions about their wealth, pensions and health care.
The findings were published in the Economic Journal.