GCF for 40 and 640

What is the Greatest Common Factor of 40 and 640?

Answer: GCF of 40 and 640 is 40

(Forty)

Finding GCF for 40 and 640 using all factors (divisors) listing

The first method to find GCF for numbers 40 and 640 is to list all factors for both numbers and pick the highest common one:

All factors of 40: 1, 2, 4, 5, 8, 10, 20, 40

All factors of 640: 1, 2, 4, 5, 8, 10, 16, 20, 32, 40, 64, 80, 128, 160, 320, 640

So the Greatest Common Factor for 40 and 640 is 40

Finding GCF for 40 and 640 by Prime Factorization

The second method to find GCF for numbers 40 and 640 is to list all Prime Factors for both numbers and multiply the common ones:

All Prime Factors of 40: 2, 2, 2, 5

All Prime Factors of 640: 2, 2, 2, 2, 2, 2, 2, 5

As we can see there are Prime Factors common to both numbers: 2, 2, 2, 5

Now we need to multiply them to find GCF: 2 × 2 × 2 × 5 = 40

GCF Table

Number 1Number 2GCF
256405
266402
276401
286404
296401
3064010
316401
3264032
336401
346402
356405
366404
376401
386402
396401
4064040
416401
426402
436401
446404
456405
466402
476401
4864016
496401
5064010
516401
526404
536401
546402

About "Greatest Common Factor" Calculator

This calculator will help you find the greatest common factor (GCF) of two numbers. For example, it can help you find out what is the Greatest Common Factor of 40 and 640? (The answer is: 40). Select the first number (e.g. '40') and the second number (e.g. '640'). After that hit the 'Calculate' button.
Greatest Common Factor (GCF) also known as the Greatest Common Divisor (GCD) or Highest Common Factor (HCF) - it is the largest positive integer that divides each of the integers with zero remainder

FAQ

What is the Greatest Common Factor of 40 and 640?

GCF of 40 and 640 is 40