Exercise 6
(1) Write the correct number in the blank box.
i)
5
7
+
2
7
=
7
7
or 1
ii)
9
8
−
1
8
= 1
iii)
6
7
+
6
7
=
12
7
iv)
11
7
−
5
14
=
17
14
v)
16
5
−
0
=
16
5
vi)
10
5
− 1 =
5
5
or 1
2. Solve.
Solution
i
1
9
+
2
9
1
9
+
2
9
=
1 + 2
9
=
3
9
=
1
3
Ans.
1
3
ii
6
10
+
3
5
LCM of 10 and 5 is 10.
6
10
+
3 × 2
5 × 2
=
6
10
+
6
10
=
12
10
Ans.
12
10
iii
2
2
3
+
3
5
7
2
2
3
=
2 × 3 + 2
3
=
8
3
3
5
7
=
3 × 7 + 5
7
=
26
7
=
8
3
+
26
7
LCM of 3 and 7 is 21.
=
8 × 7
3 × 7
+
26 × 3
7 × 3
=
56
21
+
78
21
=
134
21
=
6
8
21
Ans.
134
21
or
6
8
21
iv
13
4
−
9
4
13
4
−
9
4
=
13 − 9
4
=
4
4
= 1
Ans.
4
4
or 1
v
5
4
−
7
8
LCM of 4 and 8 is 8.
5 × 2
4 × 2
−
7
8
=
10
8
−
7
8
=
3
8
Ans.
3
8
vi
4
1
2
−
2
1
2
4
1
2
=
4 × 2 + 1
2
=
9
2
2
1
2
=
2 × 2 + 1
2
=
5
2
=
9
2
−
5
2
=
9 − 5
2
=
4
2
= 2
Ans. 2
3
Out of the 12th pass students of a junior college,
1
5
students joined the Indian Army,
2
5
students took admission for professional education and the remaining
students took admission for higher education elsewhere.
How many students took admission for higher education?
Solution
Out of total students.
1
5
students joined the Indian Army.
2
5
students took admission for professional education.
Let us find how many students took admission for higher education.
Given part,
1
5
+
2
5
=
1 + 2
5
=
3
5
Remaining part
=
1
1
−
3
5
=
5 − 3
5
=
2
5
Therefore, students went for higher education =
2
5
Ans.
2
5
part of students took admission for higher education.
4
Out of the open space in front of the school,
3
4
space was allocated for a football field and
1
5
space for indoor games. The remaining space was kept for the school garden.
How much space was kept for the school garden?
Solution
Out of the open space,
3
4
space was allocated for a football field.
1
5
space was allocated for indoor games.
Let us find the space kept for the school garden.
Given part,
LCM of 4 and 5 is 20.
3 × 5
4 × 5
+
1 × 4
5 × 4
=
15
20
+
4
20
=
19
20
Remaining part
=
1
−
19
20
=
20 − 19
20
=
1
20
Therefore, space kept for garden =
1
20
Ans.
1
20
part of space is kept for school garden.
5
Mother gave one guava each to Ramesh, Seema and their three friends.
They divided each guava into four equal parts. If each of them gave one part
of their guava to mother, What part of guava did mother get?
Solution
Mother gave one guava each to Ramesh, Seema and their three friends.
The part of guava every one given to mother =
1
4
Total persons = 5
i.e. the part of guava that mother get =
1
4
+
1
4
+
1
4
+
1
4
+
1
4
or
5 ×
1
4
=
5
4
=
1
1
4
i.e. the part of guava that mother got =
5
4
=
1
1
4
Ans. Mother got
5
4
or
1
1
4
part of guava.
6
6
7
is less than
9
11
because 6 is less than 9. Is this correct?
Solution
Among
6
7
and
9
11
LCM of 7 and 11 = 77
6
7
=
6 × 11
7 × 11
=
66
77
9
11
=
9 × 7
11 × 7
=
63
77
66
77
>
63
77
∴
6
7
>
9
11
Ans. The statement,
6
7
<
9
11
is wrong.
7
Write any two fractions whose sum is 1.
Solution
(i)
1
4
+
3
4
= 1
(ii)
2
7
+
5
7
= 1
Ans.
(i)
1
4
+
3
4
= 1
(ii) 2 7 + 5 7 = 1
(ii) 2 7 + 5 7 = 1