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What is The Concept of Multiplying by One?
Grade Level:
Pre-School – Class 2
All domains without exception
Definition
What is it?
Multiplying by one means you have a certain number of groups, and each group has exactly one item. When you multiply any number by one, the answer is always that same number. It's like counting the items you started with, but in a 'groups of one' way.
Simple Example
Quick Example
Imagine you have 5 cricket balls, and you put each ball into its own separate basket. So, you have 5 baskets, and each basket has 1 ball. How many balls do you have in total? You still have 5 balls. This is 5 multiplied by 1, which equals 5.
Worked Example
Step-by-Step
Let's say your mom gives you 7 'laddoo' sweets.
---She asks you to put each 'laddoo' on its own small plate. So, you have 7 plates.
---Each plate has exactly 1 'laddoo'.
---To find the total number of 'laddoos', you would multiply the number of plates by the number of 'laddoos' on each plate.
---Calculation: 7 plates x 1 'laddoo'/plate = 7 'laddoos'.
---So, 7 multiplied by 1 is 7.
---Answer: You have a total of 7 'laddoos'.
Why It Matters
Understanding multiplication by one is a fundamental building block for all advanced math. It helps in algebra, where '1x' is just 'x', and in understanding ratios and proportions. This simple idea is used by engineers designing bridges, by shopkeepers managing inventory, and even by scientists calculating doses of medicine.
Common Mistakes
MISTAKE: Thinking that multiplying by one makes the number bigger or smaller. For example, some might think 8 x 1 is 0 or 80. | CORRECTION: Multiplying by one means you are counting the original number of items, just grouped individually. The number stays exactly the same.
MISTAKE: Confusing multiplication by one with addition of one. For instance, thinking 9 x 1 is 9 + 1 = 10. | CORRECTION: Multiplication is repeated addition. 9 x 1 means 9 groups of 1, not 9 plus 1. So, it's 1+1+1+1+1+1+1+1+1, which is 9.
MISTAKE: Forgetting that variables also follow this rule, e.g., 'a x 1' is '1a' or 'a'. | CORRECTION: The rule applies to all numbers, including unknown values (variables). So, 'a x 1' is simply 'a'.
Practice Questions
Try It Yourself
QUESTION: A vegetable seller has 12 baskets. Each basket contains 1 pumpkin. How many pumpkins does he have in total? | ANSWER: 12 pumpkins
QUESTION: If you score 'x' marks in a test and then multiply your score by 1, what is your new score? | ANSWER: x marks
QUESTION: Your mobile data plan gives you 1 GB of data every day. If you use it for 15 days without any extra usage, and each day you count it as 1 GB, how much data have you effectively 'multiplied by one' to get your total? | ANSWER: 15 GB (because 15 days x 1 GB/day = 15 GB)
MCQ
Quick Quiz
What is the result of 25 multiplied by 1?
1
25
26
The Correct Answer Is:
C
When any number is multiplied by 1, the result is always that same number. So, 25 multiplied by 1 is 25. Options A, B, and D are incorrect because they change the original number.
Real World Connection
In the Real World
When a cashier uses a billing machine at a grocery store, if you buy 1 packet of biscuits priced at ₹30, the machine calculates 1 x ₹30 = ₹30. This simple multiplication by one ensures the correct total is added to your bill, and it happens millions of times a day in Indian shops and online transactions like UPI.
Key Vocabulary
Key Terms
MULTIPLY: To combine equal groups to find a total | PRODUCT: The answer to a multiplication problem | IDENTITY PROPERTY: The rule that says any number multiplied by 1 is itself | FACTOR: A number that is multiplied by another number
What's Next
What to Learn Next
Now that you understand multiplying by one, you're ready to learn about multiplying by zero! It's another special rule in mathematics that is just as important and equally easy to grasp once you know the basics.
