Page 72 - Ganit Kaushal

Are you not curious to know how many two-digit numbers are there from 10 to 99, three-digit numbers
from 100 to 999 and so on?

Very good, you must be! Then try to figure it out.

Digit Sums of Numbers

Add the digits of the numbers 59, 266, and 635.
What do you observe? 5 + 9 = 14

Great! You rightly observed, that the sum of the digits in all the three numbers is 2 + 6 + 6 = 14
equal —it’s 14. Such numbers are called ‘same digit sum numbers’. 6 + 3 + 5 = 14
Digit Detectives

Would you like to play the role of a ‘digit detective’ now? 337 67 667
Yes, you said. Great! After all, playing a detective is so exciting. We have lost the 575 7 2788
count of the digit 7 in the numbers 1 to 1000. Can you please figure it out for us? 7041

Exercise 3.1

1. Write the smallest and the greatest 5-digit numbers using
(a) 2, 3, 5, 8, 7 (b) 4, 9, 6, 0, 3 (c) 8, 3, 2, 0, 7
2. Write the greatest and the smallest numbers using 3, 2, 6, 0, 8 with 2 at the hundreds place.
3. Insert commas suitably and write the number names according to the Indian system of numeration.

(a) 1245678 (b) 6354793 (c) 77700087 (d) 96537801
(e) 58426973
4. Place commas correctly and write the numerals.
(a) Sixty-seven lakh eighty-two thousand six hundred one

(b) Eight crore seven lakh seventy-nine
(c) Five crore seventy-six lakh thirty-seven thousand six hundred four
(d) Ninety-one million eight hundred fifty-seven thousand six hundred nine

5. Fill in the blanks:
(a) 1 thousand = _____ tens (b) 1 lakh = _____ hundreds
(c) 1 crore = _____ lakhs (d) 1 crore = _____ thousands
(e) 1 crore = _____ millions
In questions 6 to 9, a few numbers are written on the number lines. Label the remaining marked
positions. Colour the smallest number red and the largest yellow in each of the sequences below.

6. 9997 9998

7. 2000 2010

8. 15,077 15,078 15,083

9. 86,705 87,705

70 Mathematics-6