A person\’s math ability can range from simple arithmetic to calculus and abstract set theory.But there\’s one math skill we all share: a primitive ability to estimate and compare quantities without counting, like when choosing a checkout line at the grocery store.Previous studies have suggested there\’s a connection between how well a person does at the approximate number system and how skilled they become at the symbolic math they learn in school.Duke University researchers wanted to know if this ability could be enhanced by giving people more practice at approximate …