Students in Melissa Williams' kindergarten class at the Westminster School in Atlanta, Georgia, practice connecting quantities to written numbers — a key part of number sense. Credit: Holly Korbey for ...

Imagine that someone gives you a list of five numbers: 1, 6, 21, 107 and — wait for it — 47,176,870. Can you guess what comes next? If you’re stumped, you’re not alone. These are the first five busy ...