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Multiplication – About multiplication – pg.1/8

Posted in Math Theory by Lia on 11/18/2011

Multiplication: pg. 1, 23, 4, 5, 67, 8

Contents:

pg.1…..Multiplication  – About multiplication

pg.2…..Multiplication  – Multiplication  properties

pg.3…..Multiplication  – Multiplying a number that contains multiple digits to a number that contains only one digit

pg.4…..Multiplication  – Multiplying two numbers that contain multiple digits

pg.5…..Multiplication  – Multiplying two numbers from which at least one is a decimal number

pg.6…..Multiplication – Multiplication Table

pg.7…..Multiplication – exercises

pg.8…..Multiplication – answers to exercises

 

About multiplication 

The result of multiplication is called the product.

Multiplication is the result of adding one number with itself one or more times.

Let’s consider the multiplication: {a*b} (read a times  b) This means that we add a , b times ({ underline {a + a + ... + a}under {add the number a,{}b times}})

Let’s consider the multiplication: {b*a} (read b times  a) This means that we add b , a times ({ underline {b + b + ... + b}under {add the number b,{}a times}})

Because {a*b = b*a} (commutative property of multiplication, shown below)  means that { underline {a + a + ... + a}under {add the number a,{}b times}} = { underline {b + b + ... + b}under {add the number b,{}a times}}

 

Example:

{{}{8}{}} times {{}{7}{}} can be written {8 * 7 = 56}

and it is equivalent with:

{ underline {8 + 8 + 8 + 8 + 8 + 8 + 8}under {add the number 8,{}7 times} = 56}

or

{underline {7 + 7 + 7 + 7+ 7 + 7 + 7 +7}under {add the number 7,{}8 times} = 56}

When multiplying signed numbers, we multiply the absolute values of the numbers.

  • If the two numbers we are multiplying  have  same signs the result is a positive number.

Example: {(+5 ) * (+3 ) = + 15; (-4 ) * (-6 ) = + 24}

  • If the two numbers we are multiplying have different signs the result is a negative number.

Example: {(+6 ) * (-3 ) = - 18; (-4 ) * (+ 8 ) = - 32}

 

 

Multiplication: pg. 1, 23, 4, 5, 6,  7, 8


 

 

 

 

 

 

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