1,058 is not a prime number but a composite one.

670 is not a prime number but a composite one.

* A composite number is a natural number that has at least one other factor than 1 and itself.

The two numbers have common prime factors.

1,058 ÷ 670 = 1 + 388

Step 2. Divide the smaller number by the above operation's remainder:

670 ÷ 388 = 1 + 282

Step 3. Divide the remainder of the step 1 by the remainder of the step 2:

388 ÷ 282 = 1 + 106

Step 4. Divide the remainder of the step 2 by the remainder of the step 3:

282 ÷ 106 = 2 + 70

Step 5. Divide the remainder of the step 3 by the remainder of the step 4:

106 ÷ 70 = 1 + 36

Step 6. Divide the remainder of the step 4 by the remainder of the step 5:

70 ÷ 36 = 1 + 34

Step 7. Divide the remainder of the step 5 by the remainder of the step 6:

36 ÷ 34 = 1 + 2

Step 8. Divide the remainder of the step 6 by the remainder of the step 7:

34 ÷ 2 = 17 + 0

At this step, the remainder is zero, so we stop:

2 is the number we were looking for - the last non-zero remainder.

This is the greatest (highest) common factor (divisor).

gcf, hcf, gcd (1,058; 670) = 2

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gcf, hcf, gcd (1,058; 670) = 2

The two numbers have common prime factors.

The gcf, hcf, gcd (1,058 and 670) = ? | Sep 29 08:22 UTC (GMT) |

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The greatest (highest) common factor (divisor), gcf (hcf, gcd): the list of all the calculations |

- Note 1: The greatest common factor (gcf) is also called the highest common factor (hcf), or the greatest common divisor (gcd).
- Note 2: The
**Prime Factorization**of a number: finding the prime numbers that multiply together to make that number. **Suppose the number "t" evenly divides the number "a" ( = when evenly dividing the number "a" by "t", the remainder is zero)**.- When we look at the prime factorization of "a" and "t", we find that:
- 1) all the prime factors of "t" are also prime factors of "a"
- and
- 2) the exponents of the prime factors of "t" are equal to or smaller than the exponents of the prime factors of "a" (see the * Note below)

**For example, the number 12 is a divisor (a factor) of the number 60:**- 12 = 2 × 2 × 3 = 2
^{2}× 3 - 60 = 2 × 2 × 3 × 5 = 2
^{2}× 3 × 5 *** Note:**2^{3}= 2 × 2 × 2 = 8. We say that 2 was raised to the power of 3. In this example, 3 is the exponent and 2 is the base. The exponent indicates how many times the base is multiplied by itself. 2^{3}is the power and 8 is the value of the power.

**If the number "t" is a common divisor of the numbers "a" and "b", then:**- 1) "t" only has the prime factors that also intervene in the prime factorization of "a" and "b".
- and
- 2) each prime factor of "t" has the smallest exponents with respect to the prime factors of the numbers "a" and "b".

**For example, the number 12 is the common divisor of the numbers 48 and 360.**Below is their prime factorization:- 12 = 2
^{2}× 3 - 48 = 2
^{4}× 3 - 360 = 2
^{3}× 3^{2}× 5 - You can see that the number 12 has only the prime factors that also occur in the prime factorization of the numbers 48 and 360.
- You can see above that the numbers 48 and 360 have several common factors: 2, 3, 4, 6, 8, 12, 24. Out of these, 24 is the greatest common factor (GCF) of 48 and 360.
- 24 = 2 × 2 × 2 × 3 = 2
^{3}× 3 - 48 = 2
^{4}× 3 - 360 = 2
^{3}× 3^{2}× 5 - 24, the greatest common factor of the numbers 48 and 360, is calculated as
**the product of all the common prime factors of the two numbers, taken by the smallest exponents (powers)**.

- If two numbers "a" and "b" have no other common factor than 1, gcf (a, b) = 1, then the numbers "a" and "b" are called
**coprime numbers (relatively prime, prime to each other)**. - If "a" and "b" are not relatively prime numbers, then every common divisor of "a" and "b" is a divisor of the greatest common divisor of "a" and "b".

**Let's have an example**on how to calculate the greatest common factor, gcf, of the following numbers:- 1,260 = 2
^{2}× 3^{2} - 3,024 = 2
^{4}× 3^{2}× 7 - 5,544 = 2
^{3}× 3^{2}× 7 × 11 - gcf (1,260, 3,024, 5,544) = 2
^{2}× 3^{2}= 252

**And another example:**- 900 = 2
^{2}× 3^{2}× 5^{2} - 270 = 2 × 3
^{3}× 5 - 210 = 2 × 3 × 5 × 7
- gcf (900, 270, 210) = 2 × 3 × 5 = 30

**And one more example:**- 90 = 2 × 3
^{2}× 5 - 27 = 3
^{3} - 22 = 2 × 11
- gcf (90, 27, 22) = 1 - The three numbers have no prime factors in common, they are relatively prime.