Predecessor and Successor (Grade 4)
Predecessor and successor are two basic concepts in the number system. The predecessor of a number is the number that comes just before it, and the successor is the number that comes just after it. In Class 4, you apply these concepts to 4-digit and 5-digit numbers.
These concepts help in counting, ordering, and understanding how numbers follow one another on the number line. Whether you are dealing with small numbers like 50 or large numbers like 99,999, the rule stays the same.
What is Predecessor and Successor - Class 4 Maths (Large Numbers)?
The predecessor of a number is obtained by subtracting 1 from it.
The successor of a number is obtained by adding 1 to it.
Predecessor = Number − 1
Successor = Number + 1
Every whole number (except 0) has a predecessor. Every whole number has a successor.
Special cases:
- The predecessor of 0 does not exist in whole numbers.
- The successor of 99,999 is 1,00,000 (one lakh) — the number crosses from 5 digits to 6 digits.
- The predecessor of 10,000 is 9,999 — the number drops from 5 digits to 4 digits.
Solved Examples
Example 1: Example 1: Finding the Successor
Problem: Find the successor of 45,678.
Solution:
Step 1: Add 1 to the number.
45,678 + 1 = 45,679
Answer: The successor of 45,678 is 45,679.
Example 2: Example 2: Finding the Predecessor
Problem: Find the predecessor of 30,000.
Solution:
Step 1: Subtract 1 from the number.
30,000 − 1 = 29,999
Answer: The predecessor of 30,000 is 29,999.
Example 3: Example 3: Crossing the 5-digit Boundary
Problem: Find the successor of 99,999.
Solution:
Step 1: Add 1 to 99,999.
99,999 + 1 = 1,00,000
Answer: The successor of 99,999 is 1,00,000 (one lakh). The number jumps from 5 digits to 6 digits.
Example 4: Example 4: Predecessor that Reduces Digits
Problem: Find the predecessor of 10,000.
Solution:
Step 1: Subtract 1 from 10,000.
10,000 − 1 = 9,999
Answer: The predecessor of 10,000 is 9,999. The number drops from 5 digits to 4 digits.
Example 5: Example 5: Finding Both Predecessor and Successor
Problem: Write the predecessor and successor of 56,300.
Solution:
Predecessor = 56,300 − 1 = 56,299
Successor = 56,300 + 1 = 56,301
Answer: Predecessor = 56,299, Successor = 56,301.
Example 6: Example 6: Finding the Number Between
Problem: Which number lies between 72,458 and 72,460?
Solution:
Step 1: The number between two numbers that differ by 2 is the successor of the smaller number.
72,458 + 1 = 72,459
Answer: The number between them is 72,459.
Example 7: Example 7: Predecessor of a Round Number
Problem: Find the predecessor of 50,000.
Solution:
50,000 − 1 = 49,999
Answer: The predecessor of 50,000 is 49,999.
Example 8: Example 8: Word Problem
Problem: Aditi's school roll number is 23,451. What are the roll numbers just before and just after hers?
Solution:
Roll number just before (predecessor) = 23,451 − 1 = 23,450
Roll number just after (successor) = 23,451 + 1 = 23,452
Answer: The roll numbers are 23,450 and 23,452.
Example 9: Example 9: Completing a Pattern
Problem: Complete the pattern: 67,997; 67,998; _____; 68,000; _____
Solution:
Step 1: Each number is the successor of the previous number.
67,998 + 1 = 67,999
68,000 + 1 = 68,001
Answer: 67,997; 67,998; 67,999; 68,000; 68,001
Example 10: Example 10: True or False
Problem: True or False — The predecessor of the successor of 84,500 is 84,500 itself.
Solution:
Step 1: Successor of 84,500 = 84,501
Step 2: Predecessor of 84,501 = 84,500
Answer: True. Finding the successor and then the predecessor brings you back to the original number.
Key Points to Remember
- Predecessor = Number − 1 (the number just before).
- Successor = Number + 1 (the number just after).
- Every whole number has a successor.
- Every whole number except 0 has a predecessor (in whole numbers).
- When subtracting 1 from a round number like 10,000 or 50,000, you get a number with 9s in the lower places (9,999 or 49,999).
- The successor of 99,999 is 1,00,000 — the digit count increases by one.
- Finding the successor and then the predecessor (or vice versa) always returns the original number.
Practice Problems
- Find the successor of 78,999.
- Find the predecessor of 60,000.
- Write the predecessor and successor of 45,005.
- What number lies between 33,499 and 33,501?
- Find the predecessor of 1,00,000.
- Dev's ticket number is 89,100. What is the ticket number just before his?
- Complete the pattern: 20,997; 20,998; _____; _____; 21,001.
Frequently Asked Questions
Q1. What is the predecessor of a number?
The predecessor of a number is the number that comes just before it. It is found by subtracting 1 from the given number. For example, the predecessor of 5,000 is 4,999.
Q2. What is the successor of a number?
The successor of a number is the number that comes just after it. It is found by adding 1 to the given number. For example, the successor of 5,000 is 5,001.
Q3. Does every number have a predecessor?
In the whole number system, every number except 0 has a predecessor. The predecessor of 1 is 0, and there is no whole number before 0.
Q4. What happens when you find the successor of 99,999?
The successor of 99,999 is 1,00,000 (one lakh). The number changes from a 5-digit number to a 6-digit number.
Q5. Can the predecessor of a number have fewer digits?
Yes. The predecessor of 10,000 is 9,999, which has 4 digits instead of 5. Similarly, the predecessor of 1,000 is 999. This happens when subtracting 1 from a power of 10.
Q6. How do you find the number between two consecutive numbers?
Two numbers that differ by 2 have exactly one number between them. Find it by adding 1 to the smaller number. For example, the number between 7,499 and 7,501 is 7,500.
Q7. What is the predecessor of the successor of a number?
The predecessor of the successor of any number is the number itself. If you add 1 and then subtract 1, you return to the original number.
Q8. Is predecessor and successor covered in Class 4 NCERT?
Yes, predecessor and successor concepts are part of the CBSE/NCERT Class 4 syllabus, particularly when studying large numbers up to 1,00,000.
Related Topics
- 4-Digit Numbers
- Comparing Large Numbers (Grade 4)
- Place Value of 4-Digit Numbers
- Expanded Form of 4-Digit Numbers
- 5-Digit Numbers
- Place Value of 5-Digit Numbers
- Ordering Large Numbers (Grade 4)
- Rounding Numbers (Grade 4)
- Estimation (Grade 4)
- Roman Numerals (I to C)
- Numbers up to 1,00,000
- Number Names for Large Numbers
