RS Aggarwal Solutions Class 6 Chapter 1 Number System Exercise 1A

 

EXERCISE-1A




Question 1

Q.1. Write the numeral for each of the following numbers:
(i) Nine thousand eighteen.
(ii) Fifty four thousand seventy-three.
(iii) Three lakh two thousand five hundred six.
(iv) Twenty lakh ten thousand eight.
(v) Six crore five lakh fifty-seven.
(vi) Two crore two lakh two thousand two hundred two.
(vii) Twelve crore twelve lakh twelve thousand twelve.
(viii) Fifteen crore fifty lakh twenty thousand sixty-eight.

Ans. (i) Nine thousand eighteen $=9,018$.
(ii) Fifty four thousand seventy three $=54,073$
(iii) Three lakh two thousand five hundred six $=3,02,506$.
(iv) Twenty lakh ten thousand eight $=20,10,008$.
(v) Six crore five lakh fifty-seven $=6,05,00,057$.
(vi) Two crore two lakh two thousand two hundred two $=2,02,02,202$.
(vii) Twelve crore twelve lakh twelve thousand twelve $=12,12,12,012$.
(viii) Fifteen crore fifty lakh twenty thousand sixty-eight $=15,50,20,068$.




Question 2

Q.2. Write each of the following numbers in words :
(i) 63,005
(ii) $7,07,075$
(iii) $34,20,019$
(iv) $3,05,09,012$
(v) $5,10,03,604$
(vi) $6,18,05,008$
(vii) $19,09,09,900$
(viii) $6,15,30,807$
(ix) $6,60,60,060$

Ans. (i) 63,005 = Sixty three thousand five.
(ii) $7,07,075=$ Seven lakh, seven thousand seventy five.
(iii) $34,20,019=$ Thirty-four lakh twenty thousand nineteen.
(iv) 3,05,09,012 = Three crore, five lakh, nine thousand twelve.
(v) 5,10,03,604 = Five crore ten lakh three thousand six hundred four.
(vi) $6,18,05,008=$ Six crore eighteen lakh five thousand eight.
(vii) $19,09,09,900=$ Nineteen crore nine lakh, nine thousand nine hundred.
(viii) $6,15,30,807=$ Six crore fifteen lakh, thirty thousand eight hundred seven.
(ix) 6,60,60,060 = Six crore sixty lakh sixty thousand sixty.





Question 3

Q.3. Write each of the following numbers in the expanded form:
(i) 15,768
(ii) $3,08,927$
(iii) $24,05,609$
(iv) $5,36,18,493$
(v) $6,06,06,006$
(vi) $9,10,10,510$

Ans.
(i) $15,768=(1 \times 10000)+(5 \times 1000)+(7 \times 100)+(6 \times 10)+(8 \times 1)$
(ii) $3,08,927=(3 \times 100000)+(8 \times 1000)+(9 \times 100)+(2 \times 10)+(7 \times 1)$
(iii) $24,05,609=(2 \times 1000000)+(4 \times 100000)+(5 \times 1000)+(6 \times 100)+(9 \times 1)$
(iv) $5,36,18,493=(5 \times 10000000)+(3 \times 1000000)+(6 \times 100000)+(1 \times 10000)+(8 \times 1000)+(4 \times 100)+$ $(9 \times 10)+(3 \times 1)$
(v) $6,06,06,006=(6 \times 10000000)+(6 \times 100000)+(6 \times 1000)+(6 \times 1)$
(vi) $9,10,10,510=(9 \times 10000000)+(1 \times 1000000)+(1 \times 10000)+(5 \times 100)+(1 \times 10)$






Question 4

Q.4. Write the corresponding numeral for each of the following:
(i) $6 \times 10000+2 \times 1000+5 \times 100+8 \times 10+4 \times 1$
(ii) $5 \times 100000+8 \times 10000+1 \times 1000+6 \times 100+2 \times 10+3 \times 1$
(iii) $2 \times 10000000+5 \times 100000+7 \times 1000+9 \times 100+5 \times 1$
(iv) $3 \times 1000000+4 \times 100000+6 \times 1000+5 \times 100+7 \times 1$.


Ans. (i) $6 \times 10000+2 \times 1000+5 \times 100+8 \times 10+4 \times 1=60000+2000+500+80+4$ $=62,584$.
(ii) $5 \times 100000+8 \times 10000+1 \times 1000+6 \times 100+2 \times 10+3 \times 1=500000+80000+1000+600+20+3$ $=5,81,623$
(iii) $2 \times 10000000+5 \times 100000+7 \times 1000+9 \times 100+5 \times 1=20000000+500000+7000+900+5=$ $2,05,07,905$
(iv) $3 \times 1000000+4 \times 100000+6 \times 1000+5 \times 100+7 \times 1=3000000+400000+6000+500+7=$ $34,06,507$






Question 5

Q. 5. Find the difference between the place values of the two nines in 79520986.


Ans. In 79520986
Value of first $9=9000000$ and value of second $9=900$
$\therefore$ Difference $=9000000-900=89,99,100$






Question 6

Q.6. Find the difference between the place value and the face value of 7 in 27650934.

Ans.
In 27650934 place value of $7=7000000$ and face value of $7=7$
$\therefore$ Difference $=7000000-7=6999993$




Question 7

Q. 7. How many 6-digit numbers are there in all?

Ans. There are 900000 6-digits numbers in all i.e. $999999-99999=900000$





Question 8

Q. 8. How many 7-digit numbers are there in all?

Ans. There are 9999999 - 999999
$=90000007$-digits numbers in all.





Question 9

Q.9. How many thousands make a lakh?

Ans. In 1,00,000, there are 100 thousands.




Question 10

Q.10. How many thousands make a crore ?

Ans. In 10000,000, there are 10000 thousands.




Question 11

Q.11. Find the difference between the number 738 and that obtained on reversing its digits.

Ans. Given Number $=738$
Reversing its digits $=837$
Difference between 738 and $837=837-738=99$





Question 12

Q.12. What comes just after 9547999 ?

Ans. Numbers after $9547999=9547999+1=9548000$



Question 13

Q.13. What comes just before 9900000 ?

Ans. Number first before $9900000=9900000-1=9899999$




Question 14

Q.14. What comes just before 10000000 ?

Ans. Number first before $10000000=10000000-1=9999999$




Question 15

Q.15. Write all 3-digits numbers using $2,3,4$, taking each digit only once.

Ans. 3-digits numbers using 2,3,4 taking each digit only once will be
$234,243,324,342,423,432$




Question 16

Q.16. Write the smallest number of different digits formed by using the digits $3,1,0,5$ and 7 .

Ans. The smallest number by using different digits 3, 1, 0, 5 and 7 will be $=10357$






Question 17

Q. 17. Write the largest number of different digits formed by using the digits $2,4,0,3,6$ and 9 .

Sol. The largest number formed by using different digits $2,4,0,3,6$ and 9 will be $=964320$.





Question 18

Q.18. Rewrite each of the following numerals with proper commas, using the international place value chart. Also, write the number name of each in the international system:
(i) 735821
(ii) 6057894
(iii) 56943821
(iv) 37502093
(v) 89350064
(vi) 90703006

Ans.

<TABLE TO BE ADDED>
(i) Seven hundred thirty five thousand eight hundred twenty-one.
(ii) Six million fifty seven thousand eight hundred ninety-four.
(iii) Fifty-six million nine hundred forty-three thousand eight hundred twenty-one.
(iv) Thirty-seven million five hundred two thousand ninety-three.
(v) Eighty-nine million three hundred fifty thousand sixty-four.
(vi) Ninety million seven hundred three thousand and six.





Question 19

Q.19. Write each of the following in figures in the international place-value chart:
(i) Thirty million one hundred five thousand sixty-three.
(ii) Fifty-two million two hundred five thousand six.
(iii) Five million five thousand five.

Ans.
<TABLE TO BE ADDED>





Question 20

Objective Questions
Tick ( $\sqrt{ }$ ) the correct answer in each of the following :
Q.20. The place value of 6 in the numeral 98612453 is
(a) 6
(b) 612453
(c) 600000
(d) 986

Ans.
(c) Because 6 is at lakh place.





Question 21

Q.21. The face value of 4 in the numeral 97243650 is
(a) 4
(b) 43650
(c) 40000
(d) none of these

Ans.
(a) Because face value is always same.





Question 22

Q.22. The difference between the place value and the face value of 5 in the numeral 87653421 is
(a) 53416
(b) 49995
(c) 4995
(d) none of these
(b) Because place value and face value of 5 in 87653421 are 50000 and 5.
$\therefore$ difference $=50000-5=49995$.





Question 23

Q. 23. The smallest counting number is
(a) 0
(b) 1
(c) 10
(d) none of these

Ans.
(b) Smallest counting number or natural number is 1.





Question 24

Q. 24. How many 4-digit numbers are there ?
(a) 8999
(b) 9000
(c) 8000
(d) none of these

Ans.
(b) Number of 4-digits numbers $=9999-999$ (i.e. these are 1000 to 9999 ) $=9000$





Question 25

Q. 25. How many 7-digit numbers are there?
(a) 8999999
(b) 9000000
(c) 1000000
(d) none of these

Ans.
(b) Number of 7-digit numbers (from 1000000 to 9999999 ) $=9999999-999999=9000000$





Question 26

Q. 26. How many 8-digit numbers are there?
(a) 99999999
(b) 89999999
(c) 90000000
(d) none of these

Ans.
(c) Numbers of 8-digit numbers (from 10000000 to 99999999 )
$=99999999-9999999=90000000$





Question 27

Q. 27. What comes just before 1000000 ?
(a) 99999
(b) 999999
(c) 9999999
(d) none of these

Ans.
(b) Because $1000000-1=999999$












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