First you express the numbers as the product of their prime factors:
28 = 2x2x7
21 = 3x7
Next you find the HCF. In this case, the HCF is 7. Finally, you multiply the numbers together and divide by the HCF. 28x21/7 = 84
Therefore the LCM of 28 and 21 is 84.
56.
The LCM is: 84
The Least Common Multiple (LCM) for 21 28 is 84.
LCM(21, 28, 42) = 84
LCM(6, 21, 28) = 84.
Of each of them on their own respectively is 28, 21 and 9. together is 252
The Least Common Multiple (LCM) for 273 21 28 is 1,092.
The Least Common Multiple (LCM) of 35, 21, and 28 is 420.
The LCM is: 672
The LCM is: 252
The LCM is: 672
First we will find LCM for first two numbers (28 and 35).Step 1: Find the GCD (Greatest Common Divisor) of 28 and 35 which is 7.Step 2: Multiply the numbers 28 and 35 together (28 * 35 = 980)Step 3: Divide the 980 with 7. (980/7 = 140)So, the LCM of 28 and 35 is 140.Now we will find the LCM of above result (140) and third number (21) using the same procedure.The LCM of 28, 35 and 21 is 420.