Grade 5 : Math : Exercise 1B

1. How many ones, tens, hundreds, thousands, ten thousands and lakhs are there in the number 8,00,000?

We read the number 8,00,000 as Eight lakhs which means
there are 8,00,000 ones in the number.
to find how many tens in the number, we have to divide the number by 10
that is,
8,00,000/10 = 80,000
hence there are 80,000 tens in the number 8,00,000
 
similarly to find how many hundreds in the number, we have to divide the number by 100
that is,
8,00,000/100 =8,000
hence there are 8,000 hundreds in the number 8,00,000

similarly to find how many thousands in the number, we have to divide the number by 1000
that is,
8,00,000/1000 =800
hence there are 800 thousands in the number 8,00,000

similarly to find how many ten thousands in the number, we have to divide the number by 10,000
that is,
8,00,000/10,000 =80
hence there are 80 ten thousands in the number 8,00,000

similarly to find how many lakhs in the number, we have to divide the number by 1,00,000
that is,
8,00,000/1,00,000 =8
hence there are 8 lakhs in the number 8,00,000

2. Write in figures (with commas)
a. Eight lakh thirty nine thousand twenty three
first let we write its place like,
L TTh Th H T O   (from right to left, we can stop till lakhs since the highest place is lakhs in the given figure)
eight lakhs, twenty nine thousand, twenty three
8,29,023 (no hundreds so hundreds place takes the value 0)

b. Twenty lakh nine hundred five

TL L TTh Th H T O
20,00,905

c. Thirty five thousand eight hundred fifty seven
 
TTh Th H T O
35,857

d. Four crore thirty seven lakh nineteen thousand
C TL L TTh Th H T O
4,37,19,000

3. Compare using < or > or =.

a. 5,87,90,456 _______ 5,78,23,567

Step 1:

First we have to check the number of digits on both side
which side has higher number of digits that number is greater '>'
Left side = 8digits
Right side = 8digits
both the sides have same number of digits
so lets move on to step 2

Step 2:

Compare each number from left to right
left side =5
right side =5
both are same,now lets move to the next number
left side = 8
right side = 7
8 is greater than 7
hence left side number > right side number
that is,
 5,87,90,456  >  5,78,23,567

b. 90,40,908________9,04,908 
here, left side number has higher number of digits
hence
90,40,908 > 9,04,908

c. 8,20,45,899 _______ 8,20,54,899

here, both are having same number of digits
as per step2, left side number is lesser than right side number
that is,
8,20,45,899 < 8,20,54,899

d. 1,40,10,178 ______ 1,40,10,720

here, both are having same number of digits
as per step2, left side number is lesser than right side number
that is,
 1,40,10,178 < 1,40,10,720

4. Make the smallest and greatest 7 digit numbers.

a. 5 , 8 , 2 , 9 , 1 , 1 , 8

To form the smallest number, arrange the given numbers in ascending form (smallest to greatest)
here,
11,25,889
To form the greatest number, arrange the given numbers in decending form (greatest to smallest)
that is,
98,85,211

b. 4 , 7, 1 , 9 , 0 , 6 , 7

To form the smallest number, arrange the given numbers in ascending form (smallest to greatest)
here, 0 is the smallest number but if we use 0 in 1st place then the number would be,
014677 = 14677 (which is not a 7 digit number,it became 6 digit number)
so we have to place 0 in 2nd place that is,
10,46,779
To form the greatest number, arrange the given numbers in decending form (greatest to smallest)
that is,
97,76,410

5. Make the smallest and greatest possible 8digit numbers by repeating the digits.

a. 3 , 6 , 1 , 7 , 8 , 9 , 2

 Given that we can repeat the digits.
there are only 7 digits which means we can repeat any one digit
To make the smallest possible 8 digit, we can repeat smallest digit twice
here, the smallest digit is 1 so,
1,12,36,789
To make the greatest possible 8 digit, we can repeat greatest digit twice
here, the greatest digit is 9 so,
9,98,76,321

b. 4 , 7 , 1, 0 , 3 , 5

given, there are 6 digits, but we have to frame 8digit numbers
so
To make the smallest possible 8 digit, we can repeat smallest digit thrice
here, the smallest digit is 0
since smallest digit is 0, it shouldnt be in 1st position
hence, 1,00,03,457
To make the greatest possible 8 digit, we can repeat greatest digit thrice
here, the greatest digit is 7 so,
7,77,54,310

6. Give the number before

a. 45,69,500

To find the previous number just subtract 1 from the number
so,  45,69,500 - 1 = 45,69,499

b. 87,16,000

87,16,000 - 1 = 87,15,999

c. 5,10,000
5,10,000 - 1 = 5,09,999

d. 20,00,000

20,00,000 - 1 = 19,99,999

7. Give the number after.

a. 9,26,499

To find the next number just add 1 to the number
so, 9,26,499 + 1 = 9,26,500

b. 79,98,999

79,98,999 + 1 = 79,99,000

c. 99,99,999

99,99,999 + 1 =1,00,00,000

d. 1,98,97,950

1,98,97,950 + 1 = 1,98,97,951

8. If you are 10years old, you would have lived 52,56,000 minutes. Compare the numbers given below and match the age to the minutes lived. Do not calculate. Match by putting the numbers in ascending order. One has done for you.
Age 11 - 57,81,600 (given), age12, age13, age14, age15 and minutes 68,32,800 - 63,07,200 - 73,58,400 - 78,84,000
Lets arrange in ascending (smallest to greatest) of both age and minutes correspondingly,

Age 11 - 57,81,600

Age 12 - 63,07,200

Age 13 - 68,32,800

Age 14 - 73,58,400

Age 15 - 78,84,000