Multiplication: Multi Digit and Mental Math

Multiplication is a mathematical operation that represents the repeated addition of a number. For example, 4 x 3 means adding 4 three times (4 + 4 + 4) which equals 12.

A multi-digit number is a number that has two or more digits. For example, 23, 456, and 1,234 are all multi-digit numbers.

To multiply a two-digit number by a one-digit number, you can break the two-digit number into tens and ones, multiply each part by the one-digit number, and then add the results. For example, to calculate 23 x 4, do (20 x 4) + (3 x 4) = 80 + 12 = 92.

10,000

342

49,404

4,514

640,000

The distributive property states that a(b + c) = ab + ac. This means you can distribute the multiplication over addition.

Mental math is the ability to perform calculations in your head without using a calculator or paper.