Multiply

Multiplying whole numbers

Multiplication is a mathematical operation that indicates how many times a number is added to itself.

2 x 5 = 10                                        5 + 5 = 10

Multiplying two groups of 5           Adding two groups of 5

2x5

 

 

 

Multiplication is repeated addition.  Add repeatedly (or skip-count) to multiply

2 x 5 = 10

2 x 5 = 2 + 2 + 2 + 2 + 2 = 10

Multiply

 

 

 

Multiplicand is a number that is to be multiplied by another (the multiplier). Product is the result of multiplying two (or more) numbers, for instance, 10 is the product of 2 and 5.

 

Product

Factors are the numbers that are multiplied together.

Long multiplication (traditional method)

In this method we multiply the multiplicand by each digit of the multiplier and then add up all the properly shifted results.

Multiplication

Steps:

Step one: Multiply by ones digit to get the first partial product.

Step two: Multiply by tens digit to get the second partial product.

Step three: Multiply by hundreds digit to get the third partial product.

Step four: …

Last step: Add all partial products together to get the final product! 

Example:

In this example, we multiply by the units and the tens separately.

34x21

34 x 21 = 34 x (20 + 1) = 34 x 20 + 34 x1 =680 + 34 = 714 

The box method (partial products method) works by splitting each number into tens and units

Example:   34 = 30+4  and   21 = 20+1

BoxMul

 

 

 

 

34 x 21 = 600+80+30+4 = 714

Introduction to Multiplication

What is multiplication?

Properties of Multiplication

The Distributive Property

 

IN07     Multiply

IN08     Multiply2

On a separate sheet of paper, multiply and check your answers.

Word Problems – Using Whole Numbers 

WN16  Multiply_Integers

WN17  Whole Number Multiplication

Multiply by Powers of Ten

PT21  One-Digit × Positive Powers of Ten

PT22  Two-Digits × Positive Powers of Ten 1

PT23      Two-Digits × Positive Powers of Ten 2

PT27      One-Digit × Multiples of Positive Powers of Ten

PT25      One-Digit × Multiples of Negative Powers of Ten

Multiplication properties