PPT: The Dairy Farm | Mathematics (Maths Mela) Class 5 - New NCERT PDF Download

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The Dairy Farm
Page 2


The Dairy Farm
What is Multiplication?
Multiplication means making equal groups.
Example: 6 × 2 means 6 groups of 2.
It is the same as repeated addition (2 + 2 + 2 + 2 + 2 + 2).
Page 3


The Dairy Farm
What is Multiplication?
Multiplication means making equal groups.
Example: 6 × 2 means 6 groups of 2.
It is the same as repeated addition (2 + 2 + 2 + 2 + 2 + 2).
Key Properties of Multiplication
Commutative Property
a × b = b × a
Example: 7 × 6 = 42 and 6 × 
7 = 42
Multiplicative Identity
a × 1 = a
Example: 13 × 1 = 13
Multiplication by Zero
a × 0 = 0
Example: 9 × 0 = 0
Distributive Property
a × (b + c) = (a × b) + (a × c)
Example: 12 × (10 + 2) = (12 × 10) + (12 × 2) = 120 
+ 24 = 144
Doubling & Halving Rule
If one number is halved and the other is doubled 
³ product stays same.
Example: 3 × 18 = 54 and 6 × 9 = 54
Page 4


The Dairy Farm
What is Multiplication?
Multiplication means making equal groups.
Example: 6 × 2 means 6 groups of 2.
It is the same as repeated addition (2 + 2 + 2 + 2 + 2 + 2).
Key Properties of Multiplication
Commutative Property
a × b = b × a
Example: 7 × 6 = 42 and 6 × 
7 = 42
Multiplicative Identity
a × 1 = a
Example: 13 × 1 = 13
Multiplication by Zero
a × 0 = 0
Example: 9 × 0 = 0
Distributive Property
a × (b + c) = (a × b) + (a × c)
Example: 12 × (10 + 2) = (12 × 10) + (12 × 2) = 120 
+ 24 = 144
Doubling & Halving Rule
If one number is halved and the other is doubled 
³ product stays same.
Example: 3 × 18 = 54 and 6 × 9 = 54
Order of Numbers in Multiplication
At a dairy farm, Nida stacks milk packets in 6 crates, with 13 packets in each crate. Find the total number of packets.
Ans:  13 × 6 = 78 packets. 
Now, if she rearranges them as 13 crates with 6 packets in each, will the total change?
This is written as 6 × 13. The total is still 78! 
The number of packets does not change; only the way we arrange them 
changes.
This is called the Commutative Property of multiplication.
a × b = b × a
This works for any two numbers, including tens and hundreds.
Example: 8 × 20 = 8 × (2 tens) = 16 tens = 160, and 20 × 8 is the same total.
Anything multiplied by 0 gives 0.
Page 5


The Dairy Farm
What is Multiplication?
Multiplication means making equal groups.
Example: 6 × 2 means 6 groups of 2.
It is the same as repeated addition (2 + 2 + 2 + 2 + 2 + 2).
Key Properties of Multiplication
Commutative Property
a × b = b × a
Example: 7 × 6 = 42 and 6 × 
7 = 42
Multiplicative Identity
a × 1 = a
Example: 13 × 1 = 13
Multiplication by Zero
a × 0 = 0
Example: 9 × 0 = 0
Distributive Property
a × (b + c) = (a × b) + (a × c)
Example: 12 × (10 + 2) = (12 × 10) + (12 × 2) = 120 
+ 24 = 144
Doubling & Halving Rule
If one number is halved and the other is doubled 
³ product stays same.
Example: 3 × 18 = 54 and 6 × 9 = 54
Order of Numbers in Multiplication
At a dairy farm, Nida stacks milk packets in 6 crates, with 13 packets in each crate. Find the total number of packets.
Ans:  13 × 6 = 78 packets. 
Now, if she rearranges them as 13 crates with 6 packets in each, will the total change?
This is written as 6 × 13. The total is still 78! 
The number of packets does not change; only the way we arrange them 
changes.
This is called the Commutative Property of multiplication.
a × b = b × a
This works for any two numbers, including tens and hundreds.
Example: 8 × 20 = 8 × (2 tens) = 16 tens = 160, and 20 × 8 is the same total.
Anything multiplied by 0 gives 0.
Multiplying by 10, 100, and 1000
Multiplying by 10
When we multiply a number by 10, it becomes 10 times larger, and each digit moves one place value to the left.
Example: 24 × 10 = 240
Multiplying by 100
Multiplying by 100 makes the number 100 times larger, shifting each digit two place values to the left.
Example: 24 × 100 = 2,400
Multiplying by 1000
Multiplying by 1000 makes the number 1000 times larger, shifting each digit three place values to the left.
Example: 24 × 1000 = 24,000