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What is the Previous Number in a Sequence?
Grade Level:
Pre-School – Class 2
All domains without exception
Definition
What is it?
The 'previous number' in a sequence is simply the number that comes just before a given number. It's like looking backward one step on a number line. We find it by subtracting 1 from the current number.
Simple Example
Quick Example
Imagine you are counting your cricket scores. If your last score was 50 runs, the previous score would be 49 runs. You just take one run away from 50 to get the number that came before it.
Worked Example
Step-by-Step
Let's find the previous number for 75.
Step 1: Understand what 'previous' means. It means the number that comes just before.
---Step 2: To find the number that comes just before, we subtract 1 from the given number.
---Step 3: Our given number is 75.
---Step 4: Subtract 1 from 75. So, 75 - 1.
---Step 5: 75 - 1 = 74.
Answer: The previous number for 75 is 74.
Why It Matters
Understanding previous numbers is fundamental for counting, ordering, and even simple calculations. It's crucial for subjects like data analysis, where you might track changes over time, or in computer programming when dealing with sequences. It helps build a strong foundation for advanced math concepts and problem-solving in fields like finance or engineering.
Common Mistakes
MISTAKE: Adding 1 instead of subtracting 1. Students sometimes confuse 'previous' with 'next'. | CORRECTION: Remember 'previous' means 'before', so you always subtract 1. 'Next' means 'after', so you add 1.
MISTAKE: Getting confused when the number is 0 or 1. For example, saying the previous number of 1 is 1. | CORRECTION: The previous number of 1 is 0 (1-1=0). The previous number of 0 is -1 (0-1=-1), if you are working with negative numbers.
MISTAKE: Forgetting to subtract 1 and just guessing a number close to it. | CORRECTION: Always perform the simple subtraction (number - 1) to be accurate. Don't guess!
Practice Questions
Try It Yourself
QUESTION: What is the previous number for 25? | ANSWER: 24
QUESTION: Your auto-rickshaw fare was ₹80. What was the fare one rupee less than that? | ANSWER: ₹79
QUESTION: If a shop sold 150 samosas yesterday, and today they sold 1 less than yesterday, how many samosas did they sell today? | ANSWER: 149 samosas
MCQ
Quick Quiz
Which operation helps you find the previous number?
Adding 1
Subtracting 1
Multiplying by 1
Dividing by 1
The Correct Answer Is:
B
To find the previous number, you need to go one step back in the counting sequence, which means subtracting 1 from the current number. Adding 1 would give you the next number.
Real World Connection
In the Real World
When you are checking your mobile data usage, if you used 2GB today and want to know how much you used just before that, or the data limit for the previous day's plan, you're often looking at previous numbers in a sequence. Similarly, when a cashier gives change, they often count backwards, using the idea of previous numbers.
Key Vocabulary
Key Terms
PREVIOUS: Coming just before in time or order | SEQUENCE: A set of numbers or objects in a particular order | SUBTRACT: To take away one number from another | NUMBER LINE: A visual representation of numbers in order
What's Next
What to Learn Next
Now that you understand previous numbers, you can explore 'What is the Next Number in a Sequence?'. This will help you understand how numbers progress and build a complete picture of number ordering.
