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How to Multiply in Math

Multiplication is an efficient technique for repeated addition. For example, the equation two plus two plus two plus two plus two can also be written as five times two, which is five groups of two. When multiplying, the two numbers being multiplied are called the factors and the answer is known as the product. There are many tricks and techniques for performing a multiplication equation, but in many cases it will depend whether you are doing one-digit multiplication or two-digit multiplication.

Instructions

  1. One Digit Multiplication

    • 1

      Read the equation and think of it in terms of groups. For example, the equation eight times four can be considered as eight groups of four.

    • 2

      Create an array, using either a pencil and paper or visually in your mind. An array consists of rows and columns of objects, such as dots. For example, the above equation eight times four can be used to create an array of eight rows of dots. Each row should contain four dots.

    • 3

      Use skip-counting to count the number of objects in the array. In this example, a student can count by eights four times: "8, 16, 24, 32," or by fours eight times: "4, 8, 12, 16, 20, 24, 28, 32."

    • 4

      As skip-counting gets easier, the process of creating the array can be dropped and skip-counting can simply be done in the student's head. Additionally, students should be encouraged to begin memorizing the multiplication facts so that eventually skip-counting will also become unnecessary.

    Two Digit Multiplication

    • 5

      Line the equation up vertically, for example, "12 x 18."

    • 6

      Divide the first number into groups of tens and ones. In this example, the number 12 can be divided into 10 and 2.

    • 7

      Use the distributive property to multiply the numbers. This means first multiply the tens in the first number by the entire second number. Then multiply the ones in the first number by the entire second number. In this example, first multiply 10 times 18 to make a product of 180. Then multiply two times 18 to make a product of 36.

    • 8

      Add the two products together to create the final product. In this example, the numbers 180 and 36 are added, to result in a final product of 216.

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