GCF for 40 and 420
"Greatest Common Factor" Calculator
What is the Greatest common Divisor of 40 and 420?
Answer: GCF of 40 and 420 is 20
(Twenty)
Finding GCF for 40 and 420 using all factors (divisors) listing
The first method to find GCF for numbers 40 and 420 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 420: 1, 2, 3, 4, 5, 6, 7, 10, 12, 14, 15, 20, 21, 28, 30, 35, 42, 60, 70, 84, 105, 140, 210, 420
So the Greatest Common Factor for 40 and 420 is 20
Finding GCF for 40 and 420 by Prime Factorization
The second method to find GCF for numbers 40 and 420 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 420: 2, 2, 3, 5, 7
As we can see there are Prime Factors common to both numbers: 2, 2, 5
Now we need to multiply them to find GCF: 2 × 2 × 5 = 20
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GCF Table
| Number 1 | Number 2 | GCF |
|---|---|---|
| 25 | 420 | 5 |
| 26 | 420 | 2 |
| 27 | 420 | 3 |
| 28 | 420 | 28 |
| 29 | 420 | 1 |
| 30 | 420 | 30 |
| 31 | 420 | 1 |
| 32 | 420 | 4 |
| 33 | 420 | 3 |
| 34 | 420 | 2 |
| 35 | 420 | 35 |
| 36 | 420 | 12 |
| 37 | 420 | 1 |
| 38 | 420 | 2 |
| 39 | 420 | 3 |
| 40 | 420 | 20 |
| 41 | 420 | 1 |
| 42 | 420 | 42 |
| 43 | 420 | 1 |
| 44 | 420 | 4 |
| 45 | 420 | 15 |
| 46 | 420 | 2 |
| 47 | 420 | 1 |
| 48 | 420 | 12 |
| 49 | 420 | 7 |
| 50 | 420 | 10 |
| 51 | 420 | 3 |
| 52 | 420 | 4 |
| 53 | 420 | 1 |
| 54 | 420 | 6 |
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 Divisor of 40 and 420? (The answer is: 20). Select the first number (e.g. '40') and the second number (e.g. '420'). 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