Question

find the LCM of and 28 , 15 , 42 by using prime factorisation with formula​

Answer 1

Answer:

= 420

Step-by-step explanation:

Lcm of

28, 15 and 42 = 2, 2, 3, 5, 7

2×2×3×5×7

4×15×7

60×7

= 420

Answer 2

Least Common Multiple is :

420

Calculate Least Common Multiple for :

28, 42 and 15

Factorize of the above numbers :

28 = 22 • 7

42 = 2 • 3 • 7

15 = 3 • 5

Build a prime factors table

Number of times each prime factor

appears in the factorization of :

Prime

Factor Number

28 Number

42 Number

15 L.C.M

(max)

2 2 1 0 2

3 0 1 1 1

5 0 0 1 1

7 1 1 0 1

LCM = 22 • 3 • 5 • 7

Least Common Multiple is :

420