GCF for 40 and 680

What is the Greatest Common Factor of 40 and 680?

Answer: GCF of 40 and 680 is 40

(Forty)

Finding GCF for 40 and 680 using all factors (divisors) listing

The first method to find GCF for numbers 40 and 680 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 680: 1, 2, 4, 5, 8, 10, 17, 20, 34, 40, 68, 85, 136, 170, 340, 680

So the Greatest Common Factor for 40 and 680 is 40

Finding GCF for 40 and 680 by Prime Factorization

The second method to find GCF for numbers 40 and 680 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 680: 2, 2, 2, 5, 17

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
256805
266802
276801
286804
296801
3068010
316801
326808
336801
3468034
356805
366804
376801
386802
396801
4068040
416801
426802
436801
446804
456805
466802
476801
486808
496801
5068010
5168017
526804
536801
546802

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 680? (The answer is: 40). Select the first number (e.g. '40') and the second number (e.g. '680'). 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 680?

GCF of 40 and 680 is 40