## Exercise-3.1

**Q1. Write all the factors of the following numbers :
(a) 24 (b) 15 (c) 21
(d) 27 (e) 12 (f) 20
(g) 18 (h) 23 (i) 36**

**Solution: Q1. **

(a) All factors of 24 are 1, 2, 3, 4, 6, 8, 12, 24.

(b) All factors of 15 are 1, 3, 5, 15.

(c) All factors of 21 are 1, 3, 7, 21.

(d) All factors of 27 are 1, 3, 9, 27.

(e) All factors of 12 are 1, 2, 3, 4, 6, 12.

(f) All factors of 20 are 1, 2, 4, 5, 10, 20.

(g) All factors of 18 are 1, 2, 3, 6, 9, 18.

(h) All factors of 23 are 1, 23.

(i) All factors of 36 are 1, 2, 3, 4, 6, 9, 12, 18, 36.

**Q2. Write first five multiples of :
(a) 5 (b) 8 (c) 9**

**Solutions: Q2. **

(a) First five multiples of 5 are 5, 10, 15, 20, 25.

(b) First five multiples of 8 are 8, 16, 24, 32, 40.

(c) First five multiples of 9 are 9, 18, 27, 36, 45.

**Q3. Match the items in column 1 with the items in column 2.**

Column 1 |
Column 2 |

(i) 35 | (a) Multiple of 8 |

(ii) 15 | (b) Multiple of 7 |

(iii) 16 | (c) Multiple of 70 |

(iv) 20 | (d) Factor of 30 |

(v) 25 | (e) Factor of 50 |

(e) Factor of 20 |

**Solution: Q3. **

(Answer is write in the front of column 1)

(i)35 (b) Multiple of 7

(ii)15 (d) Factor of 30

(iii)16 (a) Multiple of 8

(iv)20 (f) Factor of 20

(v)25 (e) Factor of 50

**Q4. Find all the multiples of 9 upto 100.**

**Solution: Q4. **

Answer- 9 x 1 = 9

9 x 2 = 18

9 x 3 = 27

9 x 4 = 36

9 x 5 = 45

9 x 6 = 54

9 x 7 = 63

9 x 8 = 72

9 x 9 = 81

9 x 10 = 90

9 X 11 = 99