Created By : Jatin Gogia
Reviewed By : Rajasekhar Valipishetty
Last Updated : Apr 06, 2023
Free LCM Calculator determines the least common multiple (LCM) between 81 and 84 the smallest integer that is 2268 that is divisible by both numbers.
Least Common Multiple (LCM) of 81 and 84 is 2268.
LCM(81,84) = 2268
Least common multiple or lowest common denominator (LCD) can be calculated in three ways;
Least common multiple can be found by multiplying the highest exponent prime factors of 81 and 84. First we will calculate the prime factors of 81 and 84.
Prime Factorization of 81
3 | 81 |
3 | 27 |
3 | 9 |
3 | 3 |
1 |
Prime factors of 81 are 3. Prime factorization of 81 in exponential form is:
81 = 34
Prime Factorization of 84
2 | 84 |
2 | 42 |
3 | 21 |
7 | 7 |
1 |
Prime factors of 84 are 2, 3,7. Prime factorization of 84 in exponential form is:
84 = 22×31×71
Now multiplying the highest exponent prime factors to calculate the LCM of 81 and 84.
LCM(81,84) = 22×34×71
LCM(81,84) = 2268
Factors of 81
List of positive integer factors of 81 that divides 81 without a remainder.
1, 3, 9, 27, 81
Factors of 84
List of positive integer factors of 84 that divides 84 without a remainder.
1, 2, 3, 4, 6, 7, 12, 14, 21, 28, 42, 84
The formula of LCM is LCM(a,b) = ( a × b) / GCF(a,b).
We need to calculate greatest common factor 81 and 84, than apply into the LCM equation.
GCF(81,84) = 3
LCM(81,84) = ( 81 × 84) / 3
LCM(81,84) = 6804 / 3
LCM(81,84) = 2268
(i) The LCM of 84 and 81 is associative
LCM of 81 and 84 = LCM of 84 and 81
1. What is the LCM of 81 and 84?
Answer: LCM of 81 and 84 is 2268.
2. What are the Factors of 81?
Answer: Factors of 81 are 1, 3, 9, 27, 81. There are 5 integers that are factors of 81. The greatest factor of 81 is 81.
3. What are the Factors of 84?
Answer: Factors of 84 are 1, 2, 3, 4, 6, 7, 12, 14, 21, 28, 42, 84. There are 12 integers that are factors of 84. The greatest factor of 84 is 84.
4. How to Find the LCM of 81 and 84?
Answer:
Least Common Multiple of 81 and 84 = 2268
Step 1: Find the prime factorization of 81
81 = 3 x 3 x 3 x 3
Step 2: Find the prime factorization of 84
84 = 2 x 2 x 3 x 7
Step 3: Multiply each factor the greater number of times it occurs in steps i) or ii) above to find the lcm:
LCM = 2268 = 2 x 2 x 3 x 3 x 3 x 3 x 7
Step 4: Therefore, the least common multiple of 81 and 84 is 2268.