March 14, 2018, is Pi Day — that’s pi, not pie — and on Wednesday, Google marks the 30th anniversary of the math-inspired holiday with a special Doodle. Pi, denoted by the Greek letter “π”, has been ...

When you subtract using large numbers, it's often better to use a written method. Column subtraction is a good written method to take one number away from another. It involves writing the smaller ...

The column method for addition is a good way to add large numbers. It involves writing one number beneath the other so that the digits for each place value line up. You then add the digits, starting ...

On average, there are as many prime numbers for which the sum of decimal digits is even as prime numbers for which it is odd. This hypothesis, first made in 1968, has recently been proven by ...