{"id":7574,"date":"2021-10-27T17:38:31","date_gmt":"2021-10-27T12:08:31","guid":{"rendered":"https:\/\/mathemerize.com\/?p=7574"},"modified":"2021-11-27T17:31:14","modified_gmt":"2021-11-27T12:01:14","slug":"how-to-find-greatest-common-divisor-gcd-or-hcf","status":"publish","type":"post","link":"https:\/\/mathemerize.com\/how-to-find-greatest-common-divisor-gcd-or-hcf\/","title":{"rendered":"How to Find Greatest Common Divisor (GCD or HCF)"},"content":{"rendered":"
Here you will learn concept of gcd ot hcf and how to find greatest common divisor or highest common factor of numbers and fractions with examples.<\/p>\n
Let’s begin –<\/p>\n
Consider two natural numbers \\(n_1\\) and \\(n_2\\).<\/p>\n
If the numbers \\(n_1\\) and \\(n_2\\) are exactly divisible by the same number x, then x is a common divisor of \\(n_1\\) and \\(n_2\\).<\/p>\n
The highest of all the common divisors of \\(n_1\\) and \\(n_2\\) is called as the GCD or HCF. This is denoted as GCD(\\(n_1\\), \\(n_2\\))<\/p>\n
\n(a) Find the standard form of the numbers.<\/p>\n
(b) Write out all the prime factors that are common to the standard form of the numbers.<\/p>\n
(c) Raise each of the common prime factors listed above to the lesser of the powers in which it appears in the standard forms of the numbers.<\/p>\n
(d) The product of the results of the previous step will be the GCD of the numbers. <\/p>\n<\/blockquote>\n
Rule for finding HCF of Fractions<\/h2>\n
HCF of two or more fractions is given by:<\/p>\n
\n\\(HCF of Numerators\\over LCM of Denominators\\)<\/p>\n<\/blockquote>\n
Example<\/span><\/strong> : Find the GCD of 150, 210, 375.<\/p>\n
Solution<\/span><\/strong> : We have the numbers, 150, 210, 375.<\/p>\n
1). Writing down the standard form of numbers.<\/p>\n
150 = \\(5 \\times 5 \\times 3 \\times 2\\)<\/p>\n
210 = \\(5 \\times 2 \\times 7 \\times 3\\)<\/p>\n
375 = \\(5 \\times 5 \\times 5 \\times 3\\)<\/p>\n
2). Writing Prime factors common to all the three numbers is \\(5^1 \\times 3^1\\).<\/p>\n
3). This will give the same result, i.e. \\(5^1 \\times 3^1\\)<\/p>\n
4). Hence, the HCF or GCD will be \\(5\\times 3\\) = 15<\/p>\n
Example<\/span><\/strong> : Find the GCD of 50, 75.<\/p>\n
Solution<\/span><\/strong> : We have the numbers, 50, 75<\/p>\n
1). Writing down the standard form of numbers.<\/p>\n
50 = \\(5 \\times 5 \\times 2 \\)<\/p>\n
75 = \\(5 \\times 5 \\times 3\\)<\/p>\n
2). Writing Prime factors common to all the two numbers is \\(5^1 \\times 5^1\\).<\/p>\n
3). This will give the same result, i.e. \\(5^1 \\times 5^1\\)<\/p>\n
4). Hence, the HCF or GCD will be \\(5\\times 5\\) = 25<\/p>\n
Some Other Rules for HCF<\/h2>\n
If the HCF of x and y is G, then the HCF of<\/p>\n
(i) x, (x + y) is also G<\/p>\n
(ii) x, (x – y) is also G<\/p>\n
(iii) (x + y), (x – y) is also G<\/p>\n\n\n