answersLogoWhite

0


Best Answer

If its an even number it will divide by '2'

If it end in '0' or '5' it will dividfe by '5'.

If neither of them work, then try '3' followed by '7'.

Fiunally if the duguts of a number sum to '9' , then it will divide , '9'.

e.g. Factors of 24.

It ends in an even number '4'

So

2)24 = 12

Keep on dividing by '2'

2)12 = 6

2)6 = 3

Since it is now an odd number , use '3'.

  1. 3 = 1

So all the factors of 24 are 2,2,2,& 3.

Try say , 15

Since it ends in '5' it will divide by '5'

Hence 5)15 = 3

No further division by '5' , then use '3'

  1. 3 = 1

Hence the factors of 15 are 3,5.

Hence try '81'

8 + 1 = 9

So 9)81 = 9

9'9' is factor of '3'

Hence 3) 9 = 3

3)3 = 1

Since there two x '9' we must do this asecond time.

Hence 3)9 = 3

3)3 = 1

Hence the factortsd of 81 ar 3,3,3,&3.

NB When testing for factors, always use prime numbers. 2,3,5,7,11,13,,17 ,19 etc.,

User Avatar

lenpollock

Lvl 15
1y ago
This answer is:
User Avatar
More answers
User Avatar

Wiki User

7y ago

There are a few ways to go about factoring. You can decide what works best for you. I always find the prime factorization first. Let's look at a random number: 108

The prime factorization can be found by using a factor tree.

108

54,2

27,2,2

9,3,2,2

3,3,3,2,2

2^2 x 3^3 = 108

Half of the factors will be less than the square root, half greater. If the number is a perfect square, there will be an equal number of factors on either side of the square root. In this case, the square root is between 10 and 11.

Adding one to the exponents of the prime factorization and multiplying them will tell you how many factors there are. In this case, the exponents are 2 and 3. Add one to each. 3 x 4 = 12

108 has 12 factors. Six of them are 10 or less, six of them are 11 or greater. All we have to do is divide the numbers one through ten into 108. If the result (quotient) turns out to be an integer, you've found a factor pair. Knowing the rules of divisibility will make that even easier.

108 is divisible by...

1 because everything is.

2 because it's even.

3 because its digits add up to a multiple of 3.

4 because its last two digits are a multiple of 4.

6 because it's a multiple of 2 and 3.

9 because its digits add up to a multiple of 9.

That's six factors less than 10. Divide them into 108. That's the rest of them.

(108,1)(54,2)(36,3)(27,4)(18,6)(12,9)

1, 2, 3, 4, 6, 9, 12, 18, 27, 36, 54, 108

Notice that all of those numbers, except for 1, can also be found in the prime factorization.

This answer is:
User Avatar

User Avatar

Wiki User

14y ago

You figure out a number's factors by figuring out what can be multiplied by any number to equal that number, like the factors of 10 are 1, 2, 5, and 10. :D

This answer is:
User Avatar

Add your answer:

Earn +20 pts
Q: How do you come up with factors for numbers?
Write your answer...
Submit
Still have questions?
magnify glass
imp
Related questions

What is the relationship between factors multiples and divisibility?

Factors go into numbers, numbers go into multiples. Divisibility shows what factors come out of what multiples.


What numbers have the most factors up to 200?

180: it has 18 factors.


What whole number up to 50 has the most factors?

Of the numbers up to 50, 48 has the most factors.


Which numbers up to and including 100 have ten proper factors?

60, 72, 84, 90 and 96 are the numbers up to and including 100 that have ten proper factors


Why do all numbers other than square numbers have an even number of factors?

Factors come in pairs. It is only in the case of a square number that the two middle factors are equal and so are counted only once.


How did you come up with 38 as the answer for what four factors add up to 48 and are between 30 and 40?

It wasn't me, but I would have come up with 33. The four factors of 33 add up to 48.


What are the composite number 100 up to 1?

All composite numbers have more than 2 factors but prime numbers have only 2 factors


How you find sum of prime numbers?

Prime numbers have only two factors which are themselves and one and they add up in the same way as composite numbers which have more than two factors


What three prime numbers when multiplied come to 165?

Numbers 3.5 and 11. The numbers are actually prime factors of 165 (165=3*5*11).


What four factors add up to 48 and are between the numbers 30 and 40?

The four factors of 33 add up to 48.


What number up to 50 has the most factors and why?

Of the numbers up to 50, 48 has the most factors because none of the others have more.


What are positive common factors?

All nonzero numbers have factors. Some numbers have some of the same factors as other numbers. These are called common factors. Some factors are positive numbers. Common factors which are positive numbers would be called positive common factors.