Good Guess

Quick, take a guess: how tall is an eight-story building? How many people can be transported per hour on a set of train tracks in France? How many barrels of oil does the U.S. import each year?

Maybe you gave these questions your best shot--or maybe you skimmed right over them, certain that such back-of-the-napkin conjecture wasn't worth your time. If you fall into the second, just-Google-it group, you may want to reconsider, especially if you're a parent. According to researchers who study the science of learning, estimation is the essential foundation for more advanced math skills. It's also crucial for...