# Find the other number when LCM and HCF given

• Difficulty Level : Medium
• Last Updated : 04 Mar, 2021

Given a number A and L.C.M and H.C.F. The task is to determine the other number B.
Examples:

```Input: A = 10, Lcm = 10, Hcf = 50.
Output: B = 50

Input: A = 5, Lcm = 25, Hcf = 4.
Output: B = 20```

Formula:-

A * B = LCM * HCF
B = (LCM * HCF)/A
Example : A = 15, B = 12
HCF = 3, LCM = 60
We can see that 3 * 60 = 15 * 12.
How does this formula work?
Since HCF divides both the numbers, let.
A = HCF * x
B = HCF * y
Note that x and y are not common factors, so LCM must include HCF, x and y.
So we can conclude.
LCM = HCF * x * y
So LCM * HCF = HCF * x * y * HCF which is equal to A * B

Below is the implementation of the above approach:

## C++

 `// CPP program to find other number from given``// HCF and LCM``#include ``using` `namespace` `std;` `// Function that will calculates``// the zeroes at the end``int` `otherNumber(``int` `A, ``int` `Lcm, ``int` `Hcf)``{``    ``return` `(Lcm * Hcf) / A;``}` `// Driver code``int` `main()``{``    ``int` `A = 8, Lcm = 8, Hcf = 1;` `    ``// Calling function.``    ``int` `result = otherNumber(A, Lcm, Hcf);` `    ``cout << ``"B = "` `<< result;` `    ``return` `0;``}`

## Java

 `// Java program to find other number from given``// HCF and LCM``class` `GFG{` `// Function that will calculates``// the zeroes at the end``static` `int` `otherNumber(``int` `A, ``int` `Lcm, ``int` `Hcf)``{``    ``return` `(Lcm * Hcf) / A;``}` `// Driver code``public` `static` `void` `main(String args[])``{``    ``int` `A = ``8``, Lcm = ``8``, Hcf = ``1``;` `    ``// Calling function.``    ``int` `result = otherNumber(A, Lcm, Hcf);` `    ``System.out.println(``"B = "``+ result);` `}``}`

## Python3

 `# Python 3 program to find other``# number from given HCF and LCM` `# Function that will calculates``# the zeroes at the end``def` `otherNumber(a, Lcm, Hcf):``    ``return` `(Lcm ``*` `Hcf) ``/``/` `A` `# Driver code``A ``=` `8``; Lcm ``=` `8``; Hcf ``=` `1` `# Calling function``result ``=` `otherNumber(A, Lcm, Hcf)``print``(``"B ="``, result)` `# This code is contributed``# by Shrikant13`

## C#

 `// C# program to find other number``// from given HCF and LCM``using` `System;` `class` `GFG``{` `// Function that will calculates``// the zeroes at the end``static` `int` `otherNumber(``int` `A, ``int` `Lcm,``                              ``int` `Hcf)``{``    ``return` `(Lcm * Hcf) / A;``}` `// Driver code``static` `public` `void` `Main(String []args)``{``    ``int` `A = 8, Lcm = 8, Hcf = 1;` `    ``// Calling function.``    ``int` `result = otherNumber(A, Lcm, Hcf);` `    ``Console.WriteLine(``"B = "` `+ result);``}``}` `// This code is contributed by Arnab Kundu`

## PHP

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## Javascript

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Output:

`B = 1`

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