Q-1: Write the next three natural numbers after 10999.
Solution:
The next three natural numbers after 10999 are 11000, 11001 and 11002.
Q-2: Write the three whole numbers occurring just before 10001.
Solution:
The three whole numbers occurring just before 10001 are 10000, 9999 and 9998.
Q-3: Which is the smallest whole number?
Solution:
The smallest whole number is 0.
Q-4: How many whole numbers are there between 32 and 53?
Solution:
The whole numbers 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.
$\therefore$ There are 20 whole numbers between 32 and 53.
Q-5: Write the successor of:
(a) 2440701 (b) 100199 (c) 1099999 (d) 2345670
Solution:
The successors are
(a) 2440701 + 1 = 2440702
(b) 100199 + 1 = 100200
(c) 1099999 + 1 = 1100000
(d) 2345670 + 1 = 2345671
Q-6: Write the predecessor of:
(a) 94 (b) 10000 (c) 208090 (d) 7654321
Solution:
The predecessors are
(a) 94 – 1 = 93
(b) 10000 – 1 = 9999
(c) 208090 – 1 = 208089
(d) 7654321 – 1 = 7654320
Q-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 (>, <) between them.
(a) 530, 503
(b) 370, 307
(c) 98765, 56789
(d) 9830415, 10023001
Solution:
(a) 530 > 503
$\therefore$ 503 is on the left side of 530 on the number line.
(b) 370 > 307
$\therefore$ 307 is on the left side of 370 on the number line.
(c) 98765 > 56789
$\therefore$ 56789 is on the left side of 98765 on the number line.
(d) 9830415 < 10023001
$\therefore$ 9830415 is on the left side of 10023001 on the number line.
Q-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.
Solution:
(a) Zero is the smallest natural number.
False, Zero is not a natural number.
(b) 400 is the predecessor of 399.
False, the predecessor of 399 is 398 because (399 – 1 = 398)
(c) Zero is the smallest whole number.
True, Zero is the smallest whole number.
(d) 600 is the successor of 599.
True, 600 is the successor of 599 because 599 + 1 = 600
(e) All natural numbers are whole numbers.
True, all natural numbers are whole numbers.
(f) All whole numbers are natural numbers.
False, 0 is a whole number but is not a natural number.
(g) The predecessor of a two-digit number is never a single-digit number.
False, the predecessor of 10 is 9.
(h) 1 is the smallest whole number.
False, 0 is the smallest whole number.
(i) The natural number 1 has no predecessor.
True, the predecessor of 1 is 0, but it is not a natural number.
(j) The whole number 1 has no predecessor.
False, 0 is the predecessor of 1 and is a whole number.
(k) The whole number 13 lies between 11 and 12.
False, 13 does not lie between 11 and 12.
(l) The whole number 0 has no predecessor.
True, the predecessor of 0 is -1 and is not a whole number.
(m) The successor of a two-digit number is always a two-digit number.
False, For example, the successor of 99 is 100
