Fundamentals of multiplication and division

​Fundamentals of Multiplication and Division

​Multiplication is repeated addition.

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Model for me:

Someone gives you two dollars each day for three days. How many dollars do you have?​

​ 2 x 3 =

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Model for me:

Someone gives you three dollars each day for two days. How many dollars do you have?​

​ 3 x 2 =

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It doesn't matter what order the factors go in for multiplication, you'll get the same product.​

​Neutral element:

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1 is called the identity of multiplication.

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Any number times 1 is itself.​

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7 x 1 = 7

1 x 7 = 7​

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Think about it: If I have 1 group of 7, what does that mean?​ If I have 7 groups of 1, what does that mean?

Multiple Choice

3567 x 78 =

• 78 x 3567 =

• 82 x 9034 =

• 3567 + 78 =

• 3567 - 78 =

Fill in the Blanks

795 x 1 =

​Ways to show multiplication

Fill in the Blanks

Solve:

$4\ \times\ 5\ =$  

Fill in the Blanks

Solve:

  $2\ \left(6\right)\ =$  

​Division is the opposite of multiplication.

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It means dividing something into equal groups.

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Show me:

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You have six dollars. You want to give the money equally to three friends.​

​Division is the opposite of multiplication.

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It means dividing something into equal groups.

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Show me:

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Three friends each give you two dollars. How much money do you get?​

​In division, the order does matter!

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6 divided by 3 is not the same as 3 divided by 6.​

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Try it out with these examples:

You have six dollars. You want to give the money equally to three friends.

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You have three dollars. You want to give the money equally to six friends.​

Fill in the Blanks

15 / 3 =

Fill in the Blanks

$70\ \div\ 10\ =$  

Fill in the Blanks

$\frac{24}{6}=$  

​Now, let's try a mix of multiplication and division...

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Make sure to look closely so you know if the problem is multiplication or division!​

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Fill in the Blanks

$10\ \times\ 5\ =$  

Fill in the Blanks

$\frac{30}{3}=$  

Fill in the Blanks

9 / 3 =

Fill in the Blanks

$18\ \div\ 9\ =$  

Fill in the Blanks

$10\ \left(2\right)\ =$  

​Multiplying and dividing positive and negative numbers

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The rules are different than the rules for adding and subtracting positive and negative numbers!​

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​Multiplying and dividing positive and negative numbers

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The rules are different than the rules for adding and subtracting positive and negative numbers!​

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​Why?

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https://www.mathsisfun.com/multiplying-negatives.html

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Multiple Choice

-5 x -8

• -40

• -13

• -45

• 40

Multiple Choice

12 x -4

• -24
• -36
• -60
• -48

Multiple Choice

-3(-4)

• -12
• 7 
• -7
• 12

Multiple Choice

-10(4)

• 40
• -14
• -40
• 14

Multiple Choice

Evaluate:
−30÷2

• −15
• 15
• 10
• −10

Multiple Choice

60 divided by -2

• 30
• 15
• -30
• -120

Multiple Choice

36 / -6

• 6
• 7
• -6
• -8

Multiple Choice

-27 / -27

• 0
• -0
• 1
• -1