40 is a yes, really nice number to work with. That feels prefer a natural an option for exploring a brand-new topic in math.

You are watching: List all the factor pairs of 40

In this lesson, us will break down 40 to find its various species of factors, watch at your properties, and also apply the an approach we offered to have the ability to factorize any kind of number.

You could be wondering what factors are? prior to we run in and find the determinants of 40, you should recognize their definition.

“A variable is a number i beg your pardon divides one more number exactly, leaving no remainder.”

This meaning uses division. It might assist to think of the the other means around, making use of multiplication:

“When multiplied together, two determinants make the initial number exactly.”


All factors of 40 pairs Primes proper Factorizing 40 Divisibility Rules just how to discover 40’s components Prime administrate of 40 no 40 Interesting? To sum Up (Pun Intended!)

All factors of 40


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

Adding the factors up, the complete is 90.

40’s appropriate factors are all its determinants except 1 and also 40.

There space 6 ideal factors because that 40: 2, 4, 5, 8, 10, 20. If us also include these up, the complete is 49.

40’s factors give the a special residential property which renders it abundant. Numbers are referred to as abundant if the sum of their ideal factors or half the amount of all their factors is bigger than them.

Both conditions are true for 40, so 40 is abundant.

Factor pairs of 40

The multiplication meaning of determinants says that two determinants can be multiply to make the original number exactly.

Two factors that multiply with each other to do the initial number are called a variable pair. If you have actually one factor, find its companion by separating the original number through the one you carry out have.


4 is a element of 40.

We can uncover its pair by splitting 40 by 4, offering the factor pair:

(4, 10)

When the pair of determinants is multiplied, us have:

4 × 10 = 40

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

If the initial number is square, that is square root is a factor. The element pair of a square root is…the square root again – that in a pair through itself!

For example, 100 is a square number, therefore 10 is in a pair with another 10! since 10×10=100.

You wouldn’t list 10 twice, for this reason square numbers have actually an odd lot of divisors. Numbers that aren’t square have actually an also amount of factors.

40 is not a square number therefore it has actually an even variety of factors – as you’ve seen! all its determinants can be matched into pairs:

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

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

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

The element pairings space the same. Rather of pairing positive determinants together, an adverse factors are paired together. The factors in each pair’s components must have the same sign, or rather they won’t multiply to provide a hopeful original number.

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

Prime factors of 40

Prime factors, as you might guess, are determinants that room prime numbers.

A prime number is one that cannot be divided by anything various other than 1 or itself.

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

Then the prime factors are 2 and 5.

A ascendancy to mental for later on is that all numbers can be written as assets of your prime factors.

We will certainly learn how to uncover the prime factorization below.

Proper Factors

We’ve simply seen the every number contends least 1 and also itself together a factor. Because that this reason, these numbers don’t tell united state anything unique or interesting about the number.

It’s often helpful to overlook 1 and the original number indigenous the perform of determinants for this reason.

Proper factors are a unique subcategory that “regular” factors.

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

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

Factorizing 40

Now you understand 40’s aspect secrets!


it’s no good just having actually the answers – it’s important to have the ability to get them.

We will currently work out how to factorize 40 and then occupational through a more difficult example to rise your confidence.

The easiest means to discover the determinants of a number is to usage a calculator. There room lots of possible factors to check, and a calculator will certainly save numerous time!

Failing that, or if she in one exam where you can’t usage a calculator, use the adhering to divisibility rules.

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

Divisibility Rules

Divisible through …?Test
1No test needed – every numbers room divisible by 1
2Even – number end in 2, 4, 6, 8, or 0
3Sum of digits is a multiple of 3
4The number do by the last 2 digits are divisible by 4
5Number ends in 0 or 5
6Divisible by 2 and also 3
7No an easy test!
8Divisible through 4 after being halved
9Sum of number is a lot of of 9
10Number ends in 0

If every else fails, there is constantly long division.

Now, every time you uncover a number the divides your number exactly, compose it under – that a factor. Then uncover its pair by dividing the original number.

Stop browsing for determinants once the number you’re splitting by becomes same to or bigger 보다 the square source of 40, which is 6.324. Therefore you have the right to stop checking at 6.

At this point, girlfriend have currently found every the factors! If you retained looking, any huge factor discovered would already be on the list in a pair v a smaller factor.

How to uncover the components of 40

We will use this an approach to 40. Despite you may discover the factors in her head, and the procedure may seem tedious, it’s necessary to understand and practice the technique.

It will certainly become 2nd nature with some exercise – this method finds all the factors and is quite fast!

detect the factors of 40

1 is our first factor since all integers room divisible through 1

40 ÷ 1 = 40

1’s pair is (1, 40)

40 is even, so the is divisible by 2.

40 ÷ 2 = 20

2’s pair is (2, 20)

Adding 40’s digits provides 4+0=4, and 4⁄3=1.333 for this reason 40 is no divisible by 3

40 ÷ 3 = 13.33…

40’s last two digits are just 40! Luckily, it’s simple to watch 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 through 5

40 ÷ 5 = 8

5’s pair is (5, 8)

40 is no divisible by 6 because it isn’t divisible by 3

40 ÷ 6 = 6.66…

We don’t have to check any kind of for any factors greater than 6 because 7 is larger than the square root of 40.

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

Prime factorization of 40

Breaking numbers down right into their prime factors lets us see “inside them” – the determinants are their structure blocks, letting us uncover relationships in between numbers wherein we can not mean it.

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

To discover a number’s prime factorization, girlfriend must first factorize it. Then, if the components are no prime, factorize this factors. This process is repetitive until all the determinants are prime!

The easiest difficulties are as soon as the original number is prime since there’s no work required! element numbers are already their own prime element – they can not be factorized or written more simply.

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

1. Don’t incorporate 1 in the factorization since it no tell girlfriend anything exciting – 1 is a variable of every number!

2. If the same element appears much more than once, girlfriend must incorporate each repetitive copy. If friend don’t, the product the the components won’t it is in the original number.

Finding the element factorization of 40 starts through a choice. Pick any kind of pair of its ideal factors and the factorization will become the same.

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

We favor to keep things neat, so we will begin with the pair v the the smallest prime aspect in it. You can start v whichever element pair friend like.

Then, save breaking the components of 40 down, trying to find primes, till the procedure cannot be repeated any type of more, and also only prime factors remain.


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

40 = 20 × 2

2 is obviously prime, so the is left alone. 20 no though, for this reason factorize that again. The the smallest prime number that goes into 20 is 2 again, so…

20 = 10 × 2

We have to do the very same for 10, and also again it’s the smallest prime variable is 2:

10 = 5 × 2

2 and 5 space both prime so we room finished. Substitute our factorizations for 20 and also 10 right into the very first factorization for 40.

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

40 = 5 × 2 × 2 × 2

If us tidy this up, it looks prefer this:

40 = 5 × 23

It might aid to visualize this process as a tree. As soon as all the factors have to be factorized, we collect the prime components from the ends of branches.

Ready to check what you have just learned? here’s something an ext challenging.

Let’s look in ~ 525, a enlarge number v a more complex factorization. The procedure is the very same as before!

Factorizing 525

1 is a factor. 1’s pair is (1, 525)

2 is not a factor since 525 is odd.

3 is a factor due to the fact that 5+2+5=12 and 12÷3=4. 3’s pair is (3, 175).

Looking in ~ the last 2 digits, we check out that 25 no divisible by 4, therefore 525 no either.

5 is a factor due to the fact that the critical digit is 5. 5’s pair is (5, 105).

6 no a factor because 525 isn’t divisible by 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, there aren’t any type of factors until 21! 21’s pair is (21, 25).

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

We stop checking here since is 23 is bigger than the square root of 525, 22.9.

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

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

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

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

The smallest prime the 525 is divisible by is 3.

525 ÷ 3 = 175

175 is not prime therefore factorize it v its the smallest prime, 5:

175 ÷ 5 = 35

35 is no prime, so the is factorized with its the smallest prime, 5:

35 ÷ 5 = 7

5 and also 7 space both element so we room done! that was how amazing quick.

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

525 = 3 × 5 × 5 × 7

Write repeated determinants as exponents to tidy up:

525 = 3 × 52 × 7

This have the right to be pictured by collecting the prime determinants at the end of the tree diagrams branches.

Isn’t 40 Interesting?

40 is used typically in the genuine world. Following time you come throughout it, think earlier to exactly how it’s factorized and see if girlfriend can find its prime factors again! here are some funny facts around 40:

There are 40 spaces top top a regular syndicate board, yet it constantly seems like an ext when she losing!Writing out 40 together forty, you have the right to see that its letters are in alphabetical order. Fourty is the just number which this is true for!-40 is the only temperature i m sorry is the same in both Fahrenheit and Celcius. To transform from Fahrenheit come Celcius, you must subtract 32, climate multiply by 5⁄9.

On height of gift a beneficial example in this lesson, 40 has numerous special nature in math. It turns up everywhere the place:

40 is a Harshad number. This an elaborate name means that its digits add up to one of its factors: 4+0=4 and also 4 is a factor.40 is the 4th pentagonal pyramidal number. This numbers stand for how numerous objects fit within pyramids with a pentagon base.40 is a semiperfect number, an interpretation that several of its suitable factors have the right to be added up to make 40. Why no it perfect, i hear girlfriend ask? that the sum of some of the proper factors, not every one of them:
20 + 10 + 8 + 2 = 40

To sum Up (Pun Intended!)

Today, friend learned the meaning of factors, proper factors, and prime factors.

We proclaimed the prime factorization and also factors the 40, taken a thorough method to find any kind of number’s factors, then offered it ~ above 40 to have its factors and prime factorization.

When the starting number is big, factoring deserve to be a tedious process.

It’s simplest with a calculator, however divisibility rules help if friend don’t have one.

Starting through 1 and also counting up, friend must inspect if the number is divisible and find the pair if that is. The search can stop as soon as you reach the square root.

Prime administer is all about breaking a number down. Factorize that and, if its components are no prime, factorize the factors! This process is repetitive until all the factors are prime.

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

We hope you know the various types of factors and feel confident sufficient to discover them!