help me reduce this number so i can understand?

Question

625/1000
I know its to divide it both by 125
but how do you get 125? is there an easy way to find that out? i got that from the internet

Answer 1

625 / 1000

lets start with a simple number from 2-9, exclude 1 since 1 is divisible by all numbers already... what number could be divisible to both 625 and 1000? if you look closely 2-4 is not possible... but when it comes to 5... yes it is divisible by 5 both 625 and 1000...
so,
625 / 5 = 125
and
1000 / 5 = 200
so that your number become...

125 / 200 , it is now less complicated number to look at but wait... lets check again if there are still numbers from 2-9 that is divisible to both 125 and 200?... if we look closely, 2-4 is still not possible except number 5... so,

125 / 5 = 25
and
200 / 5 = 40
so that you number become..

25 / 40

the number above is now more easy to understand... lets check again if there is still number from 2-9 that is divisible to both 25 and 40...

doing trial and error we come up that still 5 is divisible to both 25 and 40 so...

25 / 5 = 5
and
40 / 5 = 8
so that your number become..

5 / 8

is there any more number from 2-9 that is divisible to both 5 and 8?... i guess there is no more.. so that is the lowest form already...

although doing this technique is not always applicable to a more complex and higher numbers... it is the basic in order for you to familiarize and be adapted in manipulating numbers....

as it is said... "there are so many ways in killing a cat"

:)

Answer 2

It is called finding the GCD or Greatest Common Divisor of 625 and 1000. You can do it progressively, like this.

What number divides both 625 and 1000? Well, it must also divide their difference, 375.

What number divides 625 and 375? Well, it must also divide their difference, 250.

What number divides 375 and 250? Well, it must also divide their difference, 125.

Oh, look, 125 divides 250. It must be the GCD of 625 and 1000.

But when it is more difficult, like 266 and 855, you have to go like this: 855 take away 266 as many times as you can, that leaves 57, so the GCD of 855 and 266 will be the same as for 266 and 57. Then by taking away 57's, this comes down to the GCD of 57 and 38, and we get the answer 19.

When you get fluent at doing GCDs this way, you will be able to find the GCDs of a dozen different pairs of big numbers while your classmates are still hunting for all the prime factors of the first pair.

Answer 3

you need to factor out the primes of both numbers to find the common factors

625 = 5 * 5 * 5 * 5
1000 = 2 * 2 * 2 * 5 * 5 * 5

so 5 * 5 * 5 are the common factors
(because both 625 and 1000 have 5 * 5 * 5 in them)

5 * 5 * 5 = 125

now divide the numerator and denomonator by 125
625/1000 = (625/125)/(1000/125) = 5/8

answer is 5/8

Answer 4

Ok, it is not a one step process.

625/1000

First you try and find something you divide both numbers by.

5 or 25 are both easy to see, that you could divide both by.

625/25 = 25
1000/25=40

so now you have 25/40 , thats alot easier to work with.

now look at 25/40 and see what you can divide each by.

5 looks good

25/5=5
40/5=8

now you have 5/8

You do not need to do it all in one step.

The more you work with numbers, the more you will be able to see quickly, what you could divide by to reduce the numbers.

Answer 5

125 is the highest common denominator
What you do is: look at both numbers (in this case 625 and 1000) and figure out what numbers both have in common
example: 5, 25, 125

Answer 6

625/ 1000 = 5/8
125 is the highest common factor they both have....

Answer 7

625 / 1000 = 5/8

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