340 and 256: Calculate all the common factors (divisors) of the two numbers (and the prime factors)
The common factors (divisors) of the numbers 340 and 256
The common factors (divisors) of the numbers 340 and 256 are all the factors of their 'greatest (highest) common factor (divisor)'.
To remember:
A factor (divisor) of a natural number A is a natural number B which when multiplied by another natural number C equals the given number A:
A = B × C. Example: 60 = 2 × 30.
Both B and C are factors of A and they both evenly divide A ( = without a remainder).
Calculate the greatest (highest) common factor (divisor). Follow the two steps below.
The prime factorization of the two numbers:
The prime factorization of a number (the decomposition of the number into prime factors, breaking down the number into prime numbers): finding the prime numbers that multiply together to make that number.
340 = 22 × 5 × 17
340 is not a prime number but a composite one.
256 = 28
256 is not a prime number but a composite one.
* The natural numbers that are divisible only by 1 and themselves are called prime numbers. A prime number has exactly two factors: 1 and itself.
* A composite number is a natural number that has at least one other factor than 1 and itself.
Calculate the greatest (highest) common factor (divisor), gcf, hcf, gcd:
Multiply all the common prime factors, taken by their smallest exponents (the smallest powers).
gcf, hcf, gcd (340; 256) = 22 = 4
Find all the factors (divisors) of the greatest (highest) common factor (divisor), gcf, hcf, gcd
Multiply the prime factors involved in the prime factorization of the GCF in all their unique combinations, that give different results.
gcf, hcf, gcd = 4 = 22
Also consider the exponents of the prime factors (example: 32 = 3 × 3 = 9).
Also add 1 to the list of factors (divisors). All the numbers are divisible by 1.
All the factors (divisors) are listed below - in ascending order
The list of factors (divisors):
neither prime nor composite =
1
prime factor =
2
2
2 =
4
The final answer:
(scroll down)
340 and 256 have 3 common factors (divisors):
1; 2 and 4
out of which 1 prime factor: 2
A quick way to find the factors (the divisors) of a number is to first have its prime factorization.
Then multiply the prime factors in all the possible combinations that lead to different results and also take into account their exponents, if any.
Other similar operations to the common factors:
The latest 5 sets of calculated factors (divisors): of one number or the common factors of two numbers
Calculate all the divisors (factors) of the given numbers
How to calculate (find) all the factors (divisors) of a number:
Break down the number into prime factors. Then multiply its prime factors in all their unique combinations, that give different results.
To calculate the common factors of two numbers:
The common factors (divisors) of two numbers are all the factors of the greatest common factor, gcf.
Calculate the greatest (highest) common factor (divisor) of the two numbers, gcf (hcf, gcd).
Break down the GCF into prime factors. Then multiply its prime factors in all their unique combinations, that give different results.
Factors (divisors), common factors (common divisors), the greatest common factor, GCF (also called the greatest common divisor, GCD, or the highest common factor, HCF)
- If the number "t" is a factor (divisor) of the number "a" then in the prime factorization of "t" we will only encounter prime factors that also occur in the prime factorization of "a".
- If there are exponents involved, the maximum value of an exponent for any base of a power that is found in the prime factorization of "t" (powers, or multiplicities) is at most equal to the exponent of the same base that is involved in the prime factorization of "a".
- Hint: 23 = 2 × 2 × 2 = 8. 2 is called the base and 3 is the exponent. 23 is the power and 8 is the value of the power. We sometimes say that the number 2 is raised to the power of 3.
- For example, 12 is a factor (divisor) of 120 - the remainder is zero when dividing 120 by 12.
- Let's look at the prime factorization of both numbers and notice the bases and the exponents that occur in the prime factorization of both numbers:
- 12 = 2 × 2 × 3 = 22 × 3
- 120 = 2 × 2 × 2 × 3 × 5 = 23 × 3 × 5
- 120 contains all the prime factors of 12, and all its bases' exponents are higher than those of 12.
- If "t" is a common factor (divisor) of "a" and "b", then the prime factorization of "t" contains only the common prime factors involved in the prime factorizations of both "a" and "b".
- If there are exponents involved, the maximum value of an exponent for any base of a power that is found in the prime factorization of "t" is at most equal to the minimum of the exponents of the same base that is involved in the prime factorization of both "a" and "b".
- For example, 12 is the common factor of 48 and 360.
- The remainder is zero when dividing either 48 or 360 by 12.
- Here there are the prime factorizations of the three numbers, 12, 48 and 360:
- 12 = 22 × 3
- 48 = 24 × 3
- 360 = 23 × 32 × 5
- Please note that 48 and 360 have more factors (divisors): 2, 3, 4, 6, 8, 12, 24. Among them, 24 is the greatest common factor, GCF (or the greatest common divisor, GCD, or the highest common factor, HCF) of 48 and 360.
- The greatest common factor, GCF, of two numbers, "a" and "b", is the product of all the common prime factors involved in the prime factorizations of both "a" and "b", taken by the lowest exponents.
- Based on this rule it is calculated the greatest common factor, GCF, (or the greatest common divisor GCD, HCF) of several numbers, as shown in the example below...
- GCF, GCD (1,260; 3,024; 5,544) = ?
- 1,260 = 22 × 32
- 3,024 = 24 × 32 × 7
- 5,544 = 23 × 32 × 7 × 11
- The common prime factors are:
- 2 - its lowest exponent (multiplicity) is: min.(2; 3; 4) = 2
- 3 - its lowest exponent (multiplicity) is: min.(2; 2; 2) = 2
- GCF, GCD (1,260; 3,024; 5,544) = 22 × 32 = 252
- Coprime numbers:
- If two numbers "a" and "b" have no other common factors (divisors) than 1, gfc, gcd, hcf (a; b) = 1, then the numbers "a" and "b" are called coprime (or relatively prime).
- Factors of the GCF
- If "a" and "b" are not coprime, then every common factor (divisor) of "a" and "b" is a also a factor (divisor) of the greatest common factor, GCF (greatest common divisor, GCD, highest common factor, HCF) of "a" and "b".
Some articles on the prime numbers