Last updated at Jan. 3, 2019 by Teachoo

Transcript

Example 5 Find the common factors of 75, 60 and 210.We find factors of 75, 60, and 210 Separately Factors of 75 1 × 75 = 75 3 × 25 = 75 5 × 15 = 75 15 × 5 = 75 We stop here as 5 & 15 have occurred earlier Factors of 60 1 × 60 = 60 2 × 30 = 60 3 × 20 = 60 4 × 15 = 60 5 × 12 = 60 6 × 10 = 60 10 × 6 = 60 We stop here as 6 & 10 have occurred earlier Factors of 210 1 × 210 = 210 2 × 105 = 210 3 × 70 = 210 5 × 42 = 210 6 × 35 = 210 7 × 30 = 210 10 × 21 = 210 14 × 15 = 210 15 × 14 = 210 We stop here as 14 & 15 have occurred earlier So factors of 75 are 1, 3, 5, 15, 25, 75 So factors of 60 are 1, 2, 3, 4, 5, 6, 7, 10, 12, 15, 20, 30, 60 So factors of 210 are 1, 2, 3, 5, 6, 7, 10, 14, 15, 21, 30, 35, 42, 70, 105, 210 So Common factors are 1, 3, 5 and 15

Chapter 3 Class 6 Playing with Numbers

Concept wise

- Factors and Multiples
- Perfect number
- Prime and Composite Numbers
- Sum of prime numbers
- Prime numbers from 1 to 100
- Divisibility Tests - Divisibility by 5, 10, 2
- Divisibility Tests - Divisibility by 4, 8
- Divisibility Tests - Divisibility by 3, 6, 9
- Divisibility Tests - Divisibility by 11
- Divisibility Tests - All
- Common Multiples
- Common Factors
- More Divisibility Rules
- Factor Tree
- Prime Factorisation
- Highest Common Factor
- Lowest Common Multiple
- Statement questions on LCM
- Statement questions on HCF

About the Author

Davneet Singh

Davneet Singh is a graduate from Indian Institute of Technology, Kanpur. He has been teaching from the past 9 years. He provides courses for Maths and Science at Teachoo.