Learn how to multiply 2-digit numbers mentally with this step-by-step guide for kids. Discover simple techniques to boost calculation speed, improve mental math skills, and build confidence for ...

Learn how to partition two digit numbers to make multiplying them easier with Bitesize First and Second Level Maths.

This Maths article explains both the mental method and written method for multiplying a 2-digit number by a 1-digit number.

We'll explore how this shortcut works for both two-digit numbers multiplied by themselves, and even for multiplying two different numbers ending in 5.

But is this really the best way to multiply two big numbers together? In long multiplication, we have to multiply every digit of the first number by every digit of the second number.

Schönhage and Strassen predicted that an algorithm multiplying n -digit numbers using n * log (n) basic operations should exist, Harvey says. His paper is the first known proof that it does.

Multiplying two 10-digit numbers using traditional methods requires 10 × 10 = 10 2 = 100 small multiplications, but only around 10 1.58 ≈ 38 using Karatsuba’s method.

In long multiplication, we have to multiply every digit of the first number by every digit of the second number. If the two numbers each have N digits, that’s N2 (or N x N) multiplications altogether.