To help you understand the algorithm, the video shows a simple two-digit by two-digit multiplication. You can see that the first and last digits are essentially the result of one multiplication.

You wouldn’t use this algorithm when calculating a tip, but when it comes to multiplying large numbers, Karatsuba’s method was a big advance. And once Karatsuba opened the door to faster ...

The Common Core State Standards teach students the algorithm for multi-digit addition and subtraction in 4th grade. But some experts say it should be taught sooner.

Even for computers, the long multiplication algorithm, defined as n to the power of, could reportedly take months if each number had a billion digits.