\begin{array}{l}
\text {Q11. Fill in the blanks with the appropriate symbol } \lt \text { or } \gt : \\
(i) \quad 25 \ldots 205 \quad
(ii) \quad 170 \ldots 107 \quad
(iii) \quad 415 \ldots 514 \\
(iv) \quad 10001 \ldots 100001 \quad
(v) \quad 2300014 \ldots 2300041 \\ \\\text {Sol. (i) } \quad 25 \lt 205 \\
\text {(ii) } \quad 170 \gt 107 \\
\text {(iii) } \quad 415 \lt 514 \\
\text {(iv) } \quad 10001 \lt 100001 \\
\text {(v) } \quad 2300014 \lt 2300041 \\ \\\text {Q12. Arrange the following numbers in descending order: } \\
925,786,1100,141,325,886,0,270 \\ \\\text {Sol. Numbers in descending order is as follows: } \\
1100,925,886,786,325,270,141,0 \\ \\\text {Q13. Write the largest number of 6 digits and the smallest number of 7 digits. } \\
\text { Which one of these two is larger and by how much? } \\ \\\text {Sol. 999999 is the largest number of 6 digits.} \\
\text {And 1000000 is the smallest number of 7 digits.} \\
\text {1000000 is larger than 999999 by 1.} \\ \\\text {Q14. Write down three consecutive whole numbers just preceding 8510001 } \\ \\\text {Sol. The three consecutive whole numbers just preceding 8510001 are } \\
8510001- 1 = 8510000 \\
8510001- 2 = 8509999 \\
8510001- 3 = 8509998 \\ \\\text {Q15. Write down the next three consecutive whole numbers starting from 4009998 } \\ \\\text {Sol. The next three consecutive whole numbers starting from 4009998 are } \\
4009998 + 1 = 4009999 \\
4009998 + 2 = 4010000 \\
4009998 + 3 = 4010001 \\ \\\text {Q16. Give arguments in support of the statement that there does not exist the largest natural number. } \\ \\\text {Sol. Every natural number has its successor.} \\ \\\text {Q17. Which of the following statements are true and which are false? } \\
\text {(i) Every whole number has its successor. } \\
\text {(ii) Every whole number has its predecessor.} \\
\text {(iii) 0 is the smallest natural number.} \\
\text {(iv) 1 is the smallest whole number.} \\
\text {(v) 0 is less than every natural number.} \\
\text {(vi) Between any two whole numbers there is a whole number.} \\
\text {(vii) Between any two non-consecutive whole numbers there is a whole number.} \\
\text {(viii) The smallest 5 -digit number is the successor of the largest 4 digit number.} \\
\text {(ix) Of the given two natural numbers, the one having more digits is greater.} \\
\text {(x) The predecessor of a two digit number cannot be a single digit number.} \\
\text {(xi) If a and b are natural numbers and } a \lt b \text {, than there is a natural number c such that } a \lt c \lt b \\
\text {(xii) If a and b are whole numbers and } a \lt b\text {, then } a+1 \lt b+1 \\
\text {(xiii) The whole number 1 has 0 as predecessor. } \\
\text {(xiv) The natural number 1 has no predecessor. } \\ \\\text {Sol. (i) True. For example the successor of 0 is 1, successor of 1 is 2, successor of 2 is 3 and so on. } \\\text {(ii) False. Every whole number does not have any predecessor.} \\
\text {(iii) False. 0 is not the smallest natural number. } \\
\text {(iv) False. 1 is not the smallest whole number. } \\
\text {(v) True. 0 is less than natural numbers 1,2,3,4,5 and so on. } \\
\text {(vi) False. There is no whole number between two whole numbers.} \\
\text {(vii) True. Whole number exists between two consecutive whole numbers. } \\
\text {(viii) True. For example, 10000 is the successor of 9999 } \\
\text {(ix) True. For example, 100 is greater than 99 } \\
\text {(x) False. For example, the predecessor of 100 is 99.} \\
\text {(xi) False. Example: Natural numbers } 99 \lt 100 \gt 98 \\
\text {(xii) True. It means that } 1+2 \lt 3+1 \text { i.e.} 3 \lt 4 \\
\text {(xiii) True. We know that } 1 \gt 0 \\
\text {(xiv)True. Natural number starts from 1,2,3 and so on. } \\
\therefore \text {The natural number 1 has no predecessor.} \\ \\
\end{array}