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 ...

Number Sums is a challenging number puzzle to train your mental arithmetic. The goal is to make the sum of numbers in each row and column be equal to the clues on the side of the board. This ...

Given that humans have been studying numbers for thousands of years, you might think we know everything about the number 3. But mathematicians recently discovered something new about 3: a third way to ...

Follow the steps below to sum a column or row of a table in Microsoft Word: Place the cursor into the cell you want to calculate. A Formula dialog box will open. Type into the Formula section ...