How to Find Successor and Predecessor of a Number with Examples
The concept of successor and predecessor in maths plays a key role in mathematics and helps students understand the order and relationship among numbers. It's a topic that regularly appears in tests, worksheets, and even in real-life scenarios such as counting objects, arranging things, and coding.
What Is Successor and Predecessor in Maths?
A successor in maths is the number that comes immediately after a given number, while a predecessor is the number just before it. For example, in the sequence 7, 8, 9, the successor of 8 is 9, and the predecessor of 8 is 7. You’ll find this concept applied in areas such as counting numbers, sequencing in coding, and calendar dates.
Key Formula for Successor and Predecessor in Maths
Here’s the standard formula that always works for whole numbers:
- Successor of a number = Number + 1
- Predecessor of a number = Number – 1
Why Is Successor and Predecessor Important?
Successor and predecessor in maths are the building blocks of number sense for children. These concepts make it easier for students to understand counting, perform quick mental addition and subtraction, and recognize number patterns. Recognizing before/after relationships in numbers also helps with problem-solving in exams and daily activities.
Step-by-Step Examples
| Number | Successor | Predecessor |
|---|---|---|
| 15 | 16 | 14 |
| 1000 | 1001 | 999 |
| 43 | 44 | 42 |
| 0 | 1 | Not defined for whole numbers |
Worked Out Problem
Question: Find the successor and predecessor of 99999.
1. Given number = 999992. Successor = 99999 + 1 = 100000
3. Predecessor = 99999 – 1 = 99998
Answer: Successor is 100000, Predecessor is 99998.
Successor and Predecessor with Negative Numbers
For integers, the rule of successor (+1) and predecessor (-1) works for both positive and negative numbers. With negative numbers, the successor of –3 is –2, and the predecessor of –3 is –4. However, in the set of natural numbers (1, 2, 3, ...), there is no predecessor for 1, and in whole numbers (0, 1, 2, ...), there is no predecessor for 0.
Real-Life Use Cases & Fun Facts
You see successor and predecessor in maths in action when you:
- Turn the calendar from one day to the next (successor: today + 1 day = tomorrow)
- Check seat numbers (if you are in seat 7, your predecessor sat in seat 6, and your successor will sit in 8)
- Program loops in computer science (next/previous step)
Fun Fact: In Peano’s axioms, the concept of “successor” builds up the entire number system!
Try These Yourself
- What is the successor of 250?
- Find the predecessor of 1200.
- Is there a predecessor for 0 in whole numbers?
- Give the successor and predecessor for –5.
Frequent Errors and Misunderstandings
- Writing the same number as both successor and predecessor.
- Applying the concept to fractions or decimals incorrectly (the next/previous is not always just ±1 for non-integers).
- Forgetting zero has no predecessor in whole numbers.
Relation to Other Number Concepts
The idea of successor and predecessor is strongly linked with number line ordering, even & odd numbers, and arithmetic operations. Understanding this helps with learning addition, subtraction, and comparing numbers. For more on ordering and comparing, try our Greater Than Less Than Calculator.
Classroom Tip
A quick way to remember how to find a successor is to think "add one" to the number, and for predecessor, "subtract one." Vedantu’s experienced teachers often use number lines and simple drawing tricks to make this concept visual and easy in live classes.
More Practice: Worksheets and Activities
Practice is key for mastering successor and predecessor. Download printable worksheets or try online quizzes aligned with CBSE and NCERT standards to test your knowledge. You can also use the Math Basic Calculator for quick checks!
Useful Internal Links for More Learning
- Numbers to Words Converter
- Long Addition Calculator
- Rounding Numbers Tool
- Comparing Fractions Calculator
We explored successor and predecessor in maths — from clear definitions, formulas, and real-life examples, to helpful tricks and links for extra practice. Keep practicing with Vedantu and you’ll soon be a pro at finding successors and predecessors for any number!
FAQs on What Are Successor and Predecessor in Maths?
1. What is successor and predecessor?
In mathematics, a successor of a number is the number that comes immediately after it, while a predecessor is the number that comes immediately before it. For any given integer $n$:
- The successor is $n + 1$
- The predecessor is $n - 1$
2. What is the predecessor of 25?
The predecessor of 25 is the number that comes immediately before 25, which is 24. This can be obtained by subtracting one from 25: $25 - 1 = 24$. Students using Vedantu’s educational services can reinforce this concept through interactive number-based exercises.
3. Is 7 the predecessor of 8?
Yes, 7 is the predecessor of 8 because it comes right before 8 in the sequence of natural numbers. This means: $8 - 1 = 7$. Learning about number order and their relationships is a key part of foundational math learning at Vedantu.
4. What is the successor of 99999?
The successor of 99,999 is 100,000. The successor of a number is always one more than that number: $99,999 + 1 = 100,000$. This straightforward calculation is often practiced in early mathematics courses available on Vedantu's learning platform.
5. How to find the successor and predecessor of any whole number?
To find the successor and predecessor of any whole number, simply follow these two steps:
- Successor: Add 1 to the given number ($n + 1$)
- Predecessor: Subtract 1 from the given number ($n - 1$)
6. Why are successor and predecessor important in mathematics?
Successor and predecessor are important because they help students:
- Understand number order and counting sequences
- Develop arithmetic skills and pattern recognition
- Prepare for operations like addition and subtraction
7. Can every number have both a predecessor and a successor?
All whole numbers except 0 have both a successor and a predecessor. For 0, there is no predecessor within whole numbers, but it still has a successor (1). Negative numbers and integers always have both a successor and a predecessor. Vedantu teachers explain these special cases in foundational math courses using real-life examples for better clarity.
8. How do successor and predecessor help in learning place value concepts?
Understanding successor and predecessor helps students grasp place value by showing how numbers increment or decrement by one, and how digits change in different places. For example, moving from 99 to its successor 100 demonstrates how place value shifts. Vedantu’s math modules use visual aids and interactive exercises to reinforce this connection.
9. What is the successor of 0 and does 0 have a predecessor?
The successor of 0 is 1, since $0 + 1 = 1$. However, 0 does not have a predecessor within whole numbers because there is no whole number less than 0. In integers, the predecessor of 0 is $-1$. Vedantu provides practice problems that help students distinguish between whole numbers and integers for concepts like these.
