40 is a yes, really nice number to job-related with. That feels like a natural choice for trying out a new topic in math.

You are watching: What are all the factors of 40

In this lesson, we will malfunction 40 to find its various species of factors, look at at their properties, and also apply the technique we supplied to be able to factorize any number.

You might be wondering what determinants are? prior to we jump in and also find the factors of 40, you should understand their definition.

“A aspect is a number i m sorry divides an additional number exactly, leave no remainder.”

This meaning uses division. The might assist to think of the the other means around, using multiplication:

“When multiplied together, two factors make the original number exactly.”


All factors of 40 pairs Primes proper Factorizing 40 Divisibility Rules just how to uncover 40’s components Prime administrate of 40 isn’t 40 Interesting? To sum Up (Pun Intended!)

All determinants of 40


40 has 8 factors: 1, 2, 4, 5, 8, 10, 20, 40.

Adding the factors up, the complete is 90.

40’s appropriate factors space all its components except 1 and also 40.

There space 6 appropriate factors for 40: 2, 4, 5, 8, 10, 20. If us also add these up, the full is 49.

40’s determinants give the a special residential property which provides it abundant. Numbers are called abundant if the sum of their appropriate factors or half the sum of all their factors is bigger than them.

Both conditions are true because that 40, therefore 40 is abundant.

Factor pairs of 40

The multiplication definition of factors says that two determinants can be multiplied to do the initial number exactly.

Two components that multiply with each other to do the initial number are dubbed a aspect pair. If you have one factor, uncover its partner by dividing the initial number by the one you execute have.


4 is a aspect of 40.

We can uncover its pair by dividing 40 by 4, providing the aspect pair:

(4, 10)

When the pair of components is multiplied, us have:

4 × 10 = 40

In most cases, the factors in a pair are various from every other. This way that many numbers have an even variety of factors – every pair add to two determinants to the total.

If the original number is square, the square root is a factor. The variable pair the a square root is…the square source again – the in a pair through itself!

For example, 100 is a square number, for this reason 10 is in a pair with another 10! because 10×10=100.

You wouldn’t perform 10 twice, therefore square numbers have an odd lot of divisors. Numbers that aren’t square have actually an even amount that factors.

40 is not a square number so it has an even number of factors – together you’ve seen! all its components can be matched right into pairs:

40 = 40 × 1 40 = 20 × 2 40 = 10 × 4 40 = 8 × 5

What if we go off the beaten track and also include an unfavorable factors?

Allowing an adverse numbers to be determinants doubles the total! In these equations, making every the factors negative would still offer the correct answer that 40 every time.

The element pairings space the same. Rather of pairing positive components together, negative factors are paired together. The components in each pair’s components must have actually the very same sign, or else they i will not ~ multiply to give a optimistic original number.

40 = (-40) × (-1) 40 = (-20) × (-2) 40 = (-10) × (-4) 40 = (-8) × (-5)

Prime determinants of 40

Prime factors, as you may guess, are components that space prime numbers.

A element number is one the cannot be separated by anything various other than 1 or itself.

The determinants are 1, 2, 4, 5, 8, 10, 20 and also 40.

Then the prime factors are 2 and 5.

A dominance to psychic for later is the all numbers can be created as products of your prime factors.

We will certainly learn just how to find the prime factorization below.

Proper Factors

We’ve just seen that every number contends least 1 and itself together a factor. Because that this reason, these numbers nothing tell us anything distinct or interesting around the number.

It’s often valuable to neglect 1 and also the original number from the perform of components for this reason.

Proper determinants are a special subcategory the “regular” factors.

They space all the components except 1 and the number itself.

The suitable factors the 40 are: 2, 4, 5, 8, 10 and 20.

Factorizing 40

Now you know 40’s variable secrets!


that no good just having actually the answer – it’s essential to have the ability to get them.

We will currently work out just how to factorize 40 and then work through a more complicated example to an increase your confidence.

The easiest method to uncover the determinants of a number is to usage a calculator. There space lots of feasible factors come check, and also a calculator will certainly save lots of time!

Failing that, or if she in an exam wherein you can’t use a calculator, use the following divisibility rules.

Divide the number you want to factorize by every number, beginning from 1 and also counting up, to examine which numbers space factors.

Divisibility Rules

Divisible through …?Test
1No test required – all numbers room divisible by 1
2Even – number end in 2, 4, 6, 8, or 0
3Sum of number is a many of 3
4The number make by the last 2 digits room divisible through 4
5Number end in 0 or 5
6Divisible through 2 and also 3
7No basic test!
8Divisible through 4 after gift halved
9Sum of digits is a multiple of 9
10Number end in 0

If every else fails, over there is constantly long division.

Now, every time you find a number the divides your number exactly, compose it down – that a factor. Then find its pair by separating the initial number.

Stop browsing for components once the number you’re separating by becomes equal to or bigger 보다 the square root of 40, i m sorry is 6.324. For this reason you can stop checking at 6.

At this point, girlfriend have currently found all the factors! If you retained looking, any large factor uncovered would currently be top top the perform in a pair with a smaller sized factor.

How to find the determinants of 40

We will use this method to 40. Though you may find the factors in your head, and the procedure may seem tedious, it’s crucial to understand and also practice the technique.

It will become 2nd nature with some practice – this method finds all the factors and also is pretty fast!

recognize the determinants of 40

1 is our first factor due to the fact that all integers are divisible by 1

40 ÷ 1 = 40

1’s pair is (1, 40)

40 is even, so the is divisible through 2.

40 ÷ 2 = 20

2’s pair is (2, 20)

Adding 40’s digits offers 4+0=4, and 4⁄3=1.333 so 40 is no divisible by 3

40 ÷ 3 = 13.33…

40’s last two digits are just 40! Luckily, it’s straightforward to view that 4 is a factor

40 ÷ 4 = 10

4’s pair is (4, 10)

40’s last digit is 0, for this reason it’s divisible by 5

40 ÷ 5 = 8

5’s pair is (5, 8)

40 is no divisible through 6 due to the fact that it isn’t divisible through 3

40 ÷ 6 = 6.66…

We don’t need to check any kind of for any type of factors higher than 6 due to the fact that 7 is larger than the square root of 40.

We have actually found all of 40’s factors: 1, 2, 4, 5, 8, 10, 20, 40.

Prime administrate of 40

Breaking numbers down into their prime components lets united state see “inside them” – the factors are their structure blocks, letting us discover relationships between numbers wherein we can not expect it.

Multiplying these prime factors together will always give the original number.

To find a number’s prime factorization, girlfriend must very first factorize it. Then, if the factors are no prime, factorize these factors. This process is repeated until all the components are prime!

The easiest difficulties are as soon as the initial number is prime because there’s no occupational required! element numbers are currently their very own prime element – they cannot be factorized or written much more simply.

There are a couple of rule for keeping your final answer neat

1. Don’t encompass 1 in the factorization due to the fact that it doesn’t tell you anything amazing – 1 is a variable of every number!

2. If the same aspect appears much more than once, girlfriend must include each repetitive copy. If you don’t, the product the the factors won’t be the original number.

Finding the prime factorization of 40 starts with a choice. Pick any type of pair the its appropriate factors and also the administer will come to be the same.

If one of two people or both components in the pair are not prime, factorize them. If one of two people or both determinants are no prime, factorize these factors!

We like to keep things neat, so us will begin with the pair v the smallest prime variable in it. You have the right to start v whichever factor pair you like.

Then, store breaking the determinants of 40 down, trying to find primes, till the process cannot be repeated any kind of more, and only prime components remain.


The smallest prime number that goes right into 40 is 2, so let’s rest 40 right into the pair (2, 20)

40 = 20 × 2

2 is clear prime, so it is left alone. 20 no though, so factorize the again. The smallest prime number that goes into 20 is 2 again, so…

20 = 10 × 2

We should do the very same for 10, and also again it’s the smallest prime element is 2:

10 = 5 × 2

2 and also 5 are both element so we are finished. Substitute our factorizations for 20 and also 10 into the an initial factorization because that 40.

This provides us a solitary equation, the prime factorization the 40:

40 = 5 × 2 × 2 × 2

If us tidy this up, the looks favor this:

40 = 5 × 23

It might help to visualize this procedure as a tree. Once all the components have been factorized, we collection the prime factors from the end of branches.

Ready to test what you have actually just learned? here’s something much more challenging.

Let’s look at 525, a enlarge number with a more facility factorization. The process is the exact same as before!

Factorizing 525

1 is a factor. 1’s pair is (1, 525)

2 is no a factor due to the fact that 525 is odd.

3 is a factor since 5+2+5=12 and 12÷3=4. 3’s pair is (3, 175).

Looking at the last 2 digits, we check out that 25 no divisible through 4, therefore 525 no either.

5 is a factor since the last digit is 5. 5’s pair is (5, 105).

6 isn’t a factor since 525 no divisible through 2.

7 is a factor. 7’s pair is (7, 75).

There aren’t any much more factors until 15! 15’s pair is (15, 35).

Now, over there aren’t any kind of factors until 21! 21’s pair is (21, 25).

22 isn’t a factor because 525÷22=22.86, which is no a entirety number.

We avoid checking here because is 23 is bigger than the square source of 525, 22.9.

All determinants bigger than 22 have already been calculated together the pairs of determinants smaller than 22.

So, 525 has 12 factors: 1, 3, 5, 7, 15, 21, 25, 35, 75, 105, 175, 525.

Well done! Now, try the following step on your own.

discover the prime determinants of 525? (Open for solution)

The the smallest prime that 525 is divisible by is 3.

525 ÷ 3 = 175

175 is no prime therefore factorize it with its smallest prime, 5:

175 ÷ 5 = 35

35 is no prime, so it is factorized v its smallest prime, 5:

35 ÷ 5 = 7

5 and also 7 space both prime so we are done! the was how amazing quick.

Like before, we substitute our non-prime determinants with your prime factorization.

525 = 3 × 5 × 5 × 7

Write repeated factors as exponents to tidy up:

525 = 3 × 52 × 7

This deserve to be pictured by collecting the prime factors at the end of the tree diagrams branches.

Isn’t 40 Interesting?

40 is used generally in the actual world. Next time friend come across it, think ago to exactly how it’s factorized and also see if you can discover its prime components again! here are some fun facts around 40:

There are 40 spaces on a regular syndicate board, but it always seems like an ext when she losing!Writing out 40 together forty, you deserve to see that its letters are in alphabet order. Forty is the just number i m sorry this is true for!-40 is the just temperature i m sorry is the same in both Fahrenheit and Celcius. To convert from Fahrenheit come Celcius, you have to subtract 32, then multiply through 5⁄9.

On top of gift a valuable example in this lesson, 40 has plenty of special nature in math. It turns up anywhere the place:

40 is a Harshad number. This an intricate name method that its digits include up to among its factors: 4+0=4 and 4 is a factor.40 is the 4th pentagonal pyramidal number. These numbers stand for how numerous objects fit within pyramids with a pentagon base.40 is a semiperfect number, definition that some of its suitable factors deserve to be added up to do 40. Why no it perfect, i hear girlfriend ask? that the sum of some of the appropriate factors, not every one of them:
20 + 10 + 8 + 2 = 40

To sum Up (Pun Intended!)

Today, girlfriend learned the an interpretation of factors, suitable factors, and prime factors.

We declared the element factorization and factors the 40, understood a thorough technique to find any kind of number’s factors, then supplied it top top 40 to have its factors and prime factorization.

When the beginning number is big, factoring can be a tedious process.

It’s simplest with a calculator, yet divisibility rules aid if girlfriend don’t have one.

Starting through 1 and counting up, girlfriend must check if the number is divisible and also find its pair if it is. The search have the right to stop as soon as you reach the square root.

Prime administer is all around breaking a number down. Factorize it and, if its components are not prime, factorize the factors! This procedure is recurring until every the determinants are prime.

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The following step is come practice. Try repeating the factoring procedure on various other numbers friend like! If friend have any questions or a great 40-fact, you re welcome comment below.

We expect you recognize the various varieties of factors and also feel confident sufficient to find them!