Exercise 7.1
1.
Write the fraction
representing the shaded portion.
Solution
2.
Colour the part
according to the given fraction:
Solution
Solution
The shaded portions do not represent the given fractions
as each shape is not divided into equal parts.
4.
What fraction of a
day is 8 hours?
Solution
5. What fraction of an hour is 40 minutes?
Solution
6. Arya, Abhimanyu, and Vivek shared lunch. Arya has brought two sandwiches, one made of vegetable and one of jam. The other two boys forgot to bring their lunch. Arya agreed to share his sandwiches so that each person will have an equal share of each sandwich.
(a) How can Arya divide his sandwiches so that each
person has an equal share?
(b) What part of a sandwich will each boy receive?
Solution
a)
Arya should divide
his sandwiches into 3 equal parts and give 1 part of each sandwich so that each
person has an equal share.
7.
Kanchan dyes
dresses. She had to dye 30 dresses. She has so far finished 20 dresses. What
fraction of dresses has she finished?
Solution
She has finished 20 dresses out of 30.
8. Write the natural numbers from 2 to 12. What fraction of them are prime numbers?
Solution
Natural numbers from 2 to 12 are 2, 3, 4, 5, 6, 7, 8, 9,
10, 11 and 12
Prime numbers – 2, 3, 5, 7, 11
There are 11 natural numbers from 2 to 12 out of which 5
are prime numbers.
9.
Write the natural
numbers from 102 to 113. What fraction of them are prime numbers?
Solution
Natural numbers
from 102 to 113 are 102, 103, 104, 105, 106, 107, 108, 109, 110, 111, 112 and
113
Prime numbers – 103,
107, 109, 113
There are 12
natural numbers from 102 to 113 out of which 4 are prime numbers.
Solution
There are 8 circles out of which 4 have X’s in them.
11. Kristin received a CD player for
her birthday. She bought 3 CDs and received 5 others as gifts. What fraction of
her total CDs did she buy and what fraction did she receive as gifts?
Solution
Number of CDs
Kristin purchased = 3
Number of CDs she
received as gifts = 5
So, total number of
CDs = 8
Kristin purchased 3
CDs out of a total number of 8 CDs.
Kristin received 5
CDs out of a total number of 8 CDs.
Solution
c)
Solution
Solution
Exercise 7.3
Solution
The pairs are as follows:
a)
ii)
b)
iv)
c)
i)
d)
v)
e)
iii)
Solution
To find an
equivalent fraction, we may divide both the numerator and the denominator by the same number.
(a)
denominator 20 (b)
numerator 9 (c) denominator 30 (d) numerator 27
Solution
Numerator is 3 and denominator is
5.
We know that 5 × 4 = 20. So, we have multiply both the
numerator and denominator by 4 to find the equivalent fraction having
denominator 20.
Numerator is 3 and denominator is
5.
As the numerator should be 9 and 3 × 3 = 9, we have to multiply
both the numerator and denominator by 3 to find the equivalent fraction having
numerator 9.
Numerator is 3 and denominator is
5.
As the denominator should be 30 and 5 × 6 = 30, we have
to multiply both the numerator and denominator by 6 to find the equivalent
fraction having denominator 30.
Numerator is 3 and denominator is 5.
As the numerator should be 27 and 3 × 9 = 27, we have to
multiply both the numerator and denominator by 9 to find the equivalent
fraction having numerator 27.
As the numerator should be 9 and 36 ÷ 4 = 9, we have to divide
both the numerator and denominator by 4 to find the equivalent fraction having
numerator 9.
Numerator is 36 and denominator is 48.
As the denominator should be 4 and 48 ÷ 12 = 4, we have
to divide both the numerator and denominator by 12 to find the equivalent
fraction having denominator 4.
Solution
We see that the numerator and the denominator are
multiplied by the same number 6.
Hence the fractions are equivalent,
So, we see that
the fractions are not equivalent.
c)
The numerators 7 and 5, and the
denominators 13 and 11 are all prime numbers and hence they cannot be
equivalent fractions.
Solution
To reduce a fraction into its simplest form, find the HCF
of the numerator and the denominator and divide both by the HCF.
8. Ramesh had 20 pencils, Sheelu had 50 pencils and Jamaal had 80 pencils. After 4 months, Ramesh used up 10 pencils, Sheelu used up 25 pencils and Jamaal used up 40 pencils. What fraction did each use up? Check if each has used up an equal fraction of her/his pencils?
Solution
Yes, they have all used up an equal fraction of his/her pencils.
Solution
Exercise 7.4
1. Write shaded portion as fraction. Arrange them in ascending and descending order using correct sign ‘<’, ‘=’, ‘>’ between the fractions:
Exercise 7.4
1. Write shaded portion as fraction. Arrange them in ascending and descending order using correct sign ‘<’, ‘=’, ‘>’ between the fractions:
Solution
The above fractions in a) and b) are like fractions as they have the same denominator.
When comparing fractions with same denominator, the fraction with the greater numerator is greater.
Solution
a) When the denominators are the same, the fraction with the greater numerator is a greater fraction.
b) When we compare two unlike fractions, we first get their equivalent fractions with a denominator which is the L.C.M of the denominators of both the fractions.
c) The denominators are the same. So, the fraction with the greater numerator is a greater fraction.
d) When we compare two unlike fractions, we first get their equivalent fractions with a denominator which is the L.C.M of the denominators of both the fractions.
3. Make five more such pairs and put appropriate signs.
6. The following fractions represent just three different numbers. Separate them into three groups of equivalent fractions, by changing each one to its simplest form.
The fractions in its simplest form are as follows:
From the simplest forms, we see that there are three groups as
Solution
a) No. 5/9 is not equal to 4/5.
b) No, 9/16 is not equal to 5/9.
c) Yes, 4/5 is equal to 16/20
d) No, 1/15 is not equal to 4/30
8. Ila read 25 pages of a book containing 100 pages. Lalita read 2/5 of the same book. Who read less?
Solution
Total number of pages in the book = 100 pages
Number of pages read by Ila = 25 pages
So, Ila read lesser number of pages than Lalita.
9. Rafiq exercised for 3/6 of an hour, while Rohit exercised for ¾ of an hour. Who exercised for a longer time?
Rohit exercised for a longer time than Rafiq.
10. In a class A of 25 students, 20 passed in first class; in another class B of 30 students, 24 passed in first class. In which class was a greater fraction of students getting first class?
Solution
Total number of students in class A = 25
Number of students passed in first class = 20.
Total number of students in class B = 30
Number of students passed in first class = 24.
Both class A and B have the same fraction of students who passed in first class.
Exercise 7.5
1. Write these fractions appropriately as additions or subtractions:
Solution
Hence ‘+’ is the operation involved.
Hence ‘-’ is the operation involved.
c) The first shaded portion represents the fraction
The second shaded portion represents
and the third portion represents
.
So, we see that
Hence ‘+’ is the operation involved.
The second shaded portion represents
and the third portion represents
.
So, we see that
Hence ‘+’ is the operation involved.
3. Shubham painted 2/3 of the wall space in his room. His sister Madhavi helped and painted 1/3 of the wall space. How much did they paint together?
Solution
Space painted by them together = Space painted by Shubham + Space painted by Madhavi
Implies, they painted the entire wall.
5. Javed was given 5/7 of a basket of oranges. What fraction of oranges was left in the basket?
Solution
Exercise 7.6
2. Sarita bought 2/5 metre of ribbon and Lalita ¾ metre of ribbon. What is the total
length of the ribbon they bought?
Solution
Length of ribbon Sarita bought = 2/5 meter
Length of ribbon Lalita bought = ¾ meter
3. Naina was givenpiece of cake and Najma was given piece of cake. Find the total amount of cake was given to both of them.
Solution
Solution
The fractions from top to bottom are to be subtracted. So,
6. A piece of wire 7/8 metre long broke into two pieces. One piece was 1/4 metre long. How long is the other piece?
Solution
Length of the other broken piece = total length of the wire – length of one broken piece
7. Nandini’s house is 9/10 km from her school. She walked some distance and then took a bus for 1/2 km to reach the school. How far did she walk?
Solution
Distance covered by bus = ½ km
8. Asha and Samuel have bookshelves of the same size partly filled with books. Asha’s shelf is 5/6 th full and Samuel’s shelf is 2/5 th full. Whose bookshelf is more full? By what fraction?
Solution
9. Jaidev takes 2 1/5 minutes to walk across the school ground. Rahul takes 7/4 minutes to do the same. Who takes less time and by what fraction?
Solution
Time taken by Jaidev to walk =
Time taken by Rahul to walk across the ground =
Now, compare the fractions
Time taken by Rahul to walk across the ground =
Now, compare the fractions
So, Rahul takes lesser time than Jaidev.
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