ML Aggarwal Rational and Irrational Number Exe-1.1 Class 8 ICSE Maths Solutions. We Provide Step by Step Answer of Exe-1.1 Questions for Rational and Irrational Number as council prescribe guideline for upcoming board exam. Visit official Website CISCE for detail information about ICSE Board Class-8.
ML Aggarwal Rational and Irrational Number Exe-1.1 Class 8 ICSE Maths Solutions
| Board | ICSE |
| Publications | Avichal Publishig Company (APC) |
| Subject | Maths |
| Class | 8th |
| Chapter-1 | Rational and Irrational |
| Writer | ML Aggarwal |
| Book Name | Understanding |
| Topics | Solution of Exe-1.1 Questions |
| Edition | 2023-2024 |
Rational and Irrational Number Exe-1.1
ML Aggarwal Class 8 ICSE Maths Solutions
Page-6
Question 1. Add the following
(i) 4 / 7 and 5 / 7
(ii) 7 / – 13 and 4 / – 13
Answer :
(i) 4 / 7 and 5 / 7
Adding both the numbers
4 / 7 + 5 / 7 = (4 + 5) / 7
We get,
= 9 / 7
∴ The addition of 4 / 7 and 5 / 7 is 9 / 7
(ii) 7 / – 13 and 4 / – 13
7 / – 13 = {7 × (-1)} / {- 13 × (-1)}
= – 7 / 13
4 / – 13 = {4 × (-1)} / {- 13 × (-1)}
= – 4 / 13
Adding both the numbers
(7 / – 13) + (4 / – 13) = (- 7 – 4) / 13
= – 11 / 13
Question 2. Simplify:
(i) – 4 / 9 + 2(12/13)
(ii) 11 / -7 + 8(2\3)
Answer :
(i) – 4 / 9 + 2(12/13)
This can be written as,
– 4 / 9 + 38 / 13
Taking the L.C.M, we get,
– 4 / 9 = (-4 × 13) / (9 × 13)
We get,
= – 52 / 117
38 / 13 = (38 × 9) / (13 × 9)
We get,
= 342 / 117
Now,
Adding both numbers,
– 52 / 117 + 342 / 117 = (- 52 + 342) / 117
We get,
= 290 / 117
= 2(56/117)
Question 3. Verify the commutative property of addition for the following pairs of rational numbers.
(i) – 4 / 3 and 3 / 7
(ii) – 2 / – 5 and 1 / 3
(iii) 9 / 11 and 2 / 13
Answer :
(i) – 4 / 3 and 3 / 7
Adding both numbers,
= – 4 / 3 + 3 / 7
Taking the L.C.M.,
= (- 28 + 9) / 21
= – 19 / 21
3 / 7 + (- 4 / 3)
Again, taking the L.C.M.
= (9 – 28) / 21
= – 19 / 21
– 4 / 3 + 3 / 7 = 3 / 7 + (- 4 / 3)
(ii) – 2 / – 5 and 1 / 3
Consider,
– 2 / – 5 = { – 2 × (- 1)} / {- 5 × (- 1)}
= 2 / 5
2 / 5 + 1 / 3
Taking the L.C.M.,
= (6 + 5) / 15
= 11 / 15
1 / 3 + 2 / 5
Again, taking the L.C.M., we get,
= (5 + 6) / 15
= 11 / 15
2 / 5 + 1 / 3 = 1 / 3 + 2 / 5
(iii) 9 / 11 and 2 / 13
Adding both numbers,
= 9 / 11 + 2 / 13
Taking the L.C.M.,
= (117 + 22) / 143
= 139 / 143
And 2 / 13 + 9 / 11
Again, taking the L.C.M.
= (22 + 117) / 143
= 139 / 143
9 / 11 + 2 / 13 = 2 / 13 + 9 / 11
Question 4. Find the additive inverse of the following rational numbers:
(i) 2 / – 3
(ii) – 7 / – 12
Answer :
(i) 2 / – 3
Additive inverse of
2 / – 3 = – (2 / – 3)
= 2 / 3
(ii) – 7 / -12
Additive inverse of
– 7 / – 12 = – (- 7 / – 12)
= – 7 / 12
Rational and Irrational Number Exe-1.1
ML Aggarwal Class 8 ICSE Maths Solutions
Page-7
Question 5. Using appropriate properties of addition, find the following:
(i) 4 / 5 + 11 / 7 + (-7 / 5) + (- 2 / 7)
(ii) 3 / 7 + 4 / 9 + (- 5 / 21) + (2 / 3)
Answer :
(i) 4 / 5 + 11 / 7 + (- 7 / 5) + (- 2 / 7)
= 4 / 5 + (- 7 / 5) + 11 / 7 + (- 2 / 7)
= {4 + (- 7)} / 5 + {11 + (- 2)}/ 7
= (4 – 7) / 5 + (11 – 2) / 7
On further calculation, we get,
= – 3 / 5 + 9 / 7
Now, taking the L.C.M., we get,
= (- 21 + 45) / 35
= 24 / 35
(ii) 3 / 7 + 4 / 9 + (- 5 / 21) + 2 / 3
= 3 / 7 + (- 5 / 21) + 4 / 9 + 2 / 3
On simplifying, we get,
= {9 + (-5)} / 21 + (4 + 6) / 9
= 4 / 21 + 10 / 9
Taking the L.C.M., we get,
= (12 + 70) / 63
= 82 / 63
= 1(19/63)
Question 6. If a = – 11 / 27, b = 4 / 9 and c = – 5 / 18, then verify that a + (b + c) = (a + b) + c
Answer :
a = – 11 / 27, b = 4 / 9 and c = – 5 / 18
a + (b + c) = (a + b) + c
Consider,
L.H.S. = a + (b + c)
= – 11 / 27 + {4 / 9 + (- 5 / 18)}
= – 11 / 27 + (4 / 9 – 5 / 18)
On simplification, we get
= – 11 / 27 + (8 – 5) / 18
= – 11 / 27 + 3 / 18
Taking the L.C.M., we get,
= (- 22 + 9) / 54
= – 13 / 54
R.H.S. = (a + b) + c
= (- 11 / 27 + 4 / 9) + (- 5 / 18)
On further calculation, we get
= {(- 11 + 12) / 27} + (- 5 / 18)
= (1 / 27) + (- 5 / 18)
= (2 – 15) / 54
= – 13 / 54
Therefore,
L.H.S. = R.H.S.
— : End of ML Aggarwal Rational and Irrational Number Exe-1.1 Class 8 ICSE Maths Solutions :–
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