ML Aggarwal Rational and Irrational Number Exe-1.2 Class 8 ICSE Maths Solutions. We Provide Step by Step Answer of Exe-1.2 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-1.2 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-1.2 Questions |

Edition | 2023-2024 |

**Rational and Irrational Number Exe-1.2**

### ML Aggarwal Class 8 ICSE Maths Solutions

Page-9

**Question 1. Subtract:**

**(i) 2(3/5) from – 3 / 7**

**(ii) – 4 / 9 from 3(5/8)**

**(iii) -3(1/5) from -4(7/9)**

**Answer :**

**(i) 2(3/5) from – 3 / 7**

= – 3 / 7 – (13 / 5)

Taking the L.C.M., we get,

= (- 15 – 91) / 35

= – 106 / 35

**= -3(1/35)**

**(ii) – 4 / 9 from 3(5/8)**

This can be written as,

– 4 / 9 from 29 / 8

= 29 / 8 – (- 4 / 9)

= 29 / 8 + 4 / 9

Taking the L.C.M., we get,

= (261 + 32) / 72

= 293 / 72

**= 4(5/72)**

**(iii) -3(1/5) from -4(7/9)**

This can be written as,

= – 16 / 5 from – 43 / 9

= – 43 / 9 – (- 16 / 5)

= – 43 / 9 + 16 / 5

Taking the L.C.M., we get,

= (- 215 + 144) / 45

= – 71 / 45

**= -1(26/45)**

**Question 2. ****Sum of two rational numbers is 3/5. If one of them is -2/7, find the other.**

**Answer :**

Sum of two rational numbers is 3 / 5

One of the numbers is – 2 / 7

Hence, the other number is calculated as follows:

Other number = 3 / 5 – (- 2 / 7)

= 3 / 5 + 2 / 7

Taking the L.C.M., we get,

= (21 + 10) / 35

= 31 / 35

Hence, the other number is 31 / 35.

**Question 3. What rational number should be added to – 5 / 11 to get – 7 / 8?**

**Answer :**

According to the question

Sum of two numbers = – 7 / 8

One number = – 5 / 11

Hence, the other number is calculated as below:

Other number = – 7 / 8 – (- 5 / 11)

= – 7 / 8 + 5 / 11

Taking the L.C.M., we get,

= (- 77 + 40) / 88

= – 37 / 88

Hence, the other number is – 37 / 88.

**Question 4. What rational number should be subtracted from -4(3/5) to get -3(1/2) ?**

**Answer :**

The required number can be calculated :

**-4(3/5) -3(1/2)**

This can be written as,

(- 23 / 5) + (7 / 2)

On further calculation, we get

= (- 46 + 35) / 10

= – 11 / 10

= -1(1/10)

**Question 5. Subtract the sum of -5/7 and -8/3 from the sum of 5/2 and -11/12.**

**Answer :**

Sum of – 5 / 7 and – 8 / 3 s,

– 5 / 7 and – 8 / 3 = (- 5 / 7) + (- 8 / 3)

On further calculation,

= (- 15 – 56) / 21

= – 71 / 21

Sum of 5 / 2 and – 11 / 12 can be calculated as,

5 / 2 + (- 11 / 12) = 5 / 2 – 11 / 12

= (30 – 11) / 12

= 19 / 12

19 / 12 – (- 71 / 21)

= 19 / 12 + 71 / 21

Taking the L.C.M.,

= (133 + 284) / 84

= 417 / 84

= 4(81/84)

**Question 6. If x = – 4 / 7 and y = 2 / 5, then verify that **

**(i) x – y ≠ y – x**

**(ii) -(x+y) = (-x) + (-y)**

**Answer :**

**(i) x – y ≠ y – x**

x = – 4 / 7 and y = 2 / 5

x – y = – 4 / 7 – (2 / 5)

= – 4 / 7 – 2 / 5

Taking the L.C.M., we get,

= (- 20 – 14) / 35

= – 34 / 35

y – x = 2 / 5 – (- 4 / 7)

= 2 / 5 + 4 / 7

Taking the L.C.M., we get,

= (14 + 20) / 35

= 34 / 35

Hence, x – y ≠ y – x

**Question 7. ****If x = 4 / 9, y = – 7 / 12 and z = – 2 / 3, then verify that x – (y – z) ≠ (x – y) – z**

**Answer :**

x = 4 / 9, y = – 7 / 12, z = – 2 / 3

x – (y – z) ≠ (x – y) – z

L.H.S. = x – (y – z)

= 4 / 9 – {- 7 / 12 – (- 2 / 3)}

= 4 / 9 – (- 7 / 12 + 2 / 3)

= 4 / 9 – {(- 7 + 8) / 12}

= 4 / 9 – (1 / 12)

= 4 / 9 – 1 / 12

Taking the L.C.M.

= (16 – 3) / 36

= 13 / 36

R.H.S = (x – y) – z

= {4 / 9 – (- 7 / 12)} – (- 7 / 12)

= (4 / 9 + 7 / 12) + 7 / 12

On further calculation,

= {(16 + 21) / 36} + 7 / 12

= 37 / 36 + 7 / 12

Again taking the L.C.M.,

= (37 + 21) / 36

= 58 / 36

Hence, x – (y – z) ≠ (x – y) – z

**Question 8.** **Which of the following statement is true/false?**

(i) 2 / 3 – 4 / 5 is not a rational number.

(ii) – 5 / 7 is the additive inverse of 5 / 7.

(iii) 0 is the additive inverse of its own.

(iv) Commutative property holds for the subtraction of rational numbers.

(v) Associative property does not hold for the subtraction of rational numbers.

(vi) 0 is the identity element for the subtraction of rational numbers.

**Answer :**

**(i) 2 / 3 – 4 / 5**

Taking L.C.M

= (10 – 12) / 15

= – 2 / 15

Is a rational number

Hence, the given statement is **false.**

**(ii) The given statement is true.**

**(iii) The given statement is true.**

**(iv) Let us take,**

5 / 4 – 3 / 4 = 2 / 4

3 / 4 – 5 / 4 = – 2 / 4

2 / 4 ≠ – 2 / 4

**Hence, the given statement is false.**

**(v) The given statement is true.**

**(vi) Let us take,**

7 / 8 – 0 = 7 / 8

0 – 7 / 8 = – 7 / 8

7 / 8 ≠ – 7 / 8

**Hence, the given statement is false.**

— : End of ML Aggarwal Rational and Irrational Number Exe-1.2 Class 8 ICSE Maths Solutions :–

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