RBSE Solutions Class 6 Maths Chapter 3 Whole Numbers Exercise 3.1

Whole Numbers Ex 3.1

Question 1. Fill in the blanks
(i) Predecessor of 55 is .....................
(ii) Predecessor of 100 is .....................
(iii) Predecessor of 305 is ..................... and its successor is .....................
(iv) Whole numbers are formed by including ..................... in natural numbers.
(v) Predecessor of 1 is .....................
Answer:
(i) The predecessor of 55 is 54.
(ii) The predecessor of 100 is 99.
(iii) The predecessor of 305 is 304, and its successor is 306.
(iv) Whole numbers are formed by including 0 in natural numbers. Zero is a key part of the whole number set.
(v) The predecessor of 1 is 0.
In simple words: A predecessor is the number just before another number, found by subtracting 1. A successor is the number just after, found by adding 1. Whole numbers start from 0 and include all positive counting numbers.

🎯 Exam Tip: Remember that "predecessor" means "one less" and "successor" means "one more". Also, know that 0 is the smallest whole number and the only whole number that is not a natural number.

Question 2. Write the predecessors of the following numbers.
(i) 1203
(ii) 2406
(iii) 3555
(iv) 4444
Answer:
(i) The predecessor of 1203 is \(1203 - 1 = 1202\).
(ii) The predecessor of 2406 is \(2406 - 1 = 2405\).
(iii) The predecessor of 3555 is \(3555 - 1 = 3554\).
(iv) The predecessor of 4444 is \(4444 - 1 = 4443\). Finding a predecessor simply means finding the number that comes just before it on the number line.
In simple words: To find the predecessor of a number, you just subtract 1 from it. This tells you the number right before it.

🎯 Exam Tip: Always subtract exactly 1 to find the predecessor. Double-check your subtraction to avoid simple errors, especially with numbers ending in 0.

Question 3. Write the successors of the following numbers.
(i) 2304
Answer:
(i) The successor of 2304 is \(2304 + 1 = 2305\). A successor is the number that comes immediately after a given number.
In simple words: To find the successor, you add 1 to the number. This gives you the next number in order.

🎯 Exam Tip: For successors, always add 1. This helps you understand the sequence of numbers.

Question 4. Write the successors and predecessors of the following numbers.
(i) 189
(ii) 199
(iii) 209
(iv) 300
Answer: The numbers along with their predecessors and successors are shown in the table below. Understanding predecessors and successors helps in knowing the order of numbers.

🎯 Exam Tip: When asked for both predecessor and successor, create a clear table or list to organize your answers. This makes it easy to read and ensures you don't miss anything.

Question 5. Which is the smallest whole number?
Answer: 0 (Zero) is the smallest whole number. Whole numbers begin with 0 and include all positive integers.
In simple words: The smallest whole number is zero.

🎯 Exam Tip: Remember that natural numbers start from 1, but whole numbers include 0, making 0 the smallest whole number.

Question 6. Mark right or wrong in front of the following statements :
(i) All natural numbers are whole numbers.
(ii) 1 is the smallest whole numbers.
(iii) The sum of two whole numbers is always a whole numbers.
(iv) \(245 + 450 = 450 + 245\).
(v) \(1124 + 0 = 0\).
(vi) The operation of subtraction is reciprocal to the operation of addition.
(vii) \(4 - 4 = 0\) (is a whole numbers).
Answer:
(i) T - All natural numbers (1, 2, 3...) are included in the set of whole numbers (0, 1, 2, 3...).
(ii) F - The smallest whole number is 0, not 1.
(iii) T - When you add any two whole numbers, the result is always another whole number. This is called the closure property under addition.
(iv) T - The order of numbers in addition does not change the sum. This is known as the commutative property of addition.
(v) F - When you add 0 to any number, the number remains the same. So, \(1124 + 0 = 1124\), not 0.
(vi) F - Subtraction and addition are inverse operations, meaning they undo each other, but the term "reciprocal" is typically used for multiplication and division.
(vii) T - When you subtract a number from itself, the result is 0, which is a whole number.
In simple words: (i) True, because whole numbers include all natural numbers. (ii) False, because zero is the smallest whole number. (iii) True, because adding two whole numbers always gives a whole number. (iv) True, because changing the order in addition does not change the answer. (v) False, because adding zero to a number keeps the number the same. (vi) False, because "reciprocal" is about multiplication, not subtraction and addition. (vii) True, because zero is a whole number.

🎯 Exam Tip: Understand the definitions of natural numbers and whole numbers, and key properties of addition like commutativity and closure. Pay close attention to the special role of zero in these operations.