GSEB Class 6 Maths Solutions Chapter 2 Whole Numbers Exercise 2.1

Exercise 21 (Page 31)

Question 1. Write the next three natural numbers after 10999.
Answer: The next three natural numbers, following 10999, are: 11000, 11001, and 11002. These come one right after the other.
In simple words: Just count forward three numbers from 10999 to find the next natural numbers.

Exam Tip: Remember that natural numbers start from 1 and go upwards. To find the next numbers, simply add 1 repeatedly.

Question 2. Write the three whole numbers occurring just before 10001.
Answer: The three whole numbers that occur just before 10001 are: 10000, 9999, and 9998. These are the numbers found right before it.
In simple words: Count backward three numbers from 10001 to find the ones before it.

Exam Tip: Whole numbers include 0 and all natural numbers. When finding numbers "just before", subtract 1 sequentially.

Question 3. Which is the smallest whole number?
Answer: The smallest whole number is 0. It is the beginning of the set of whole numbers.
In simple words: Zero is the smallest whole number.

Exam Tip: Clearly distinguish between natural numbers (starting from 1) and whole numbers (starting from 0) as this is a common point of confusion.

Question 4. How many whole numbers are there between 32 and 53?
Answer: The whole numbers located between 32 and 53 are: 33, 34, 35, 36, 37, 38, 39, 40, 41, 42, 43, 44, 45, 46, 47, 48, 49, 50, 51, 52. If you count these, you will find there are 20 whole numbers altogether in that range.
In simple words: List all the whole numbers after 32 but before 53, then count them up. There are 20 numbers.

Exam Tip: When asked for numbers "between" two given numbers, do not include the starting and ending numbers themselves in your count.

Question 5. Write the successor of
(a) 2440701
(b) 100199
(c) 1099999
(d) 2345670
Answer:
(a) The successor of 2440701 is \( 2440701 + 1 = 2440702 \).
(b) The successor of 100199 is \( 100199 + 1 = 100200 \).
(c) The successor of 1099999 is \( 1099999 + 1 = 1100000 \).
(d) The successor of 2345670 is \( 2345670 + 1 = 2345671 \).
In simple words: The successor of a number is the number that comes right after it. To find it, you simply add 1 to the given number.

Exam Tip: Be careful with numbers ending in 9s, as finding their successor often involves changing multiple digits (e.g., 99 to 100).

Question 6. Write the predecessor of
(a) 94
(b) 10000
(c) 208090
(d) 7654321
Answer:
(a) The predecessor of 94 is \( 94 - 1 = 93 \).
(b) The predecessor of 10000 is \( 10000 - 1 = 9999 \).
(c) The predecessor of 208090 is \( 208090 - 1 = 208089 \).
(d) The predecessor of 7654321 is \( 7654321 - 1 = 7654320 \).
In simple words: The predecessor of a number is the number that comes right before it. To find it, you simply subtract 1 from the given number.

Exam Tip: Remember that zero (0) has no predecessor in the set of whole numbers, but it does in integers. Pay attention to the number set specified.

Question 7. In each of the following pairs of numbers, state which whole number is on the left of the other number on the number line. Also write them with the appropriate sign (>, <)
Answer:
(a) Given numbers are 530, 503.
On the number line, the whole number 503 is located to the left of 530.
Thus, \( 530 > 503 \).
(b) Given numbers are 370, 307.
On the number line, the whole number 307 is located to the left of 370.
Thus, \( 370 > 307 \).
(c) Given numbers are 98765, 56789.
On the number line, the whole number 56789 is located to the left of 98765.
Thus, \( 98765 > 56789 \).
(d) Given numbers are 9830415, 10023001.
On the number line, the whole number 9830415 is located to the left of 10023001.
Thus, \( 10023001 > 9830415 \).
In simple words: The smaller number is always on the left side of the number line. If a number is bigger, it's on the right. You use '>' for 'greater than' and '<' for 'less than'.

Exam Tip: Visualizing a number line helps to quickly determine which number is smaller (left) and which is larger (right). The mouth of the inequality sign always "eats" the larger number.

Question 8. Which of the following statements are true (T) and which are false (F)?
(a) Zero is the smallest natural number
(b) 400 is the predecessor of 399.
(c) Zero is the smallest whole number
(d) 600 is the successor of 599.
(e) All natural numbers are whole numbers.
(f) All whole numbers are natural numbers.
(g) The predecessor of a two-digit number is never a single-digit number
(h) 1 is the smallest whole number
(i) The natural number 1 has no predecessor
(j) The whole number 1 has no predecessor
(k) The whole number 13 lies between 11 and 12.
(l) The whole number 0 has no predecessor
(m)The successor of a two-digit number is always a two-digit number
Answer:
(a) Zero is the smallest natural number - False (F). Natural numbers begin with 1.
(b) 400 is the predecessor of 399 - False (F). 400 is the *successor* of 399.
(c) Zero is the smallest whole number - True (T). Whole numbers start with 0.
(d) 600 is the successor of 599 - True (T). \( 599 + 1 = 600 \).
(e) All natural numbers are whole numbers - True (T). Natural numbers are a subset of whole numbers.
(f) All whole numbers are natural numbers - False (F). Zero (0) is a whole number but not a natural number.
(g) The predecessor of a two-digit number is never a single-digit number - False (F). The predecessor of 10 (a two-digit number) is 9 (a single-digit number).
(h) 1 is the smallest whole number - False (F). Zero (0) is the smallest whole number.
(i) The natural number 1 has no predecessor - True (T). Natural numbers start from 1, so there's nothing before it in that set.
(j) The whole number 1 has no predecessor - False (F). The predecessor of 1 (a whole number) is 0 (also a whole number).
(k) The whole number 13 lies between 11 and 12 - False (F). 13 is greater than 12.
(l) The whole number 0 has no predecessor - True (T). There is no whole number smaller than 0.
(m)The successor of a two-digit number is always a two-digit number - False (F). The successor of 99 (a two-digit number) is 100 (a three-digit number).
In simple words: You need to know the definitions of natural numbers and whole numbers, and what 'predecessor' (number before) and 'successor' (number after) mean. Then, check each statement carefully.

Exam Tip: Be precise with definitions of number sets (natural vs. whole numbers) and concepts like predecessor and successor. Counter-examples can help verify false statements.