JavaScript: Least common multiple (LCM) of two numbers

JavaScript Math: Exercise-10 with Solution

LCM of Two Numbers

Write a JavaScript function to get the least common multiple (LCM) of two numbers.
Note :
According to Wikipedia - A common multiple is a number that is a multiple of two or more integers. The common multiples of 3 and 4 are 0, 12, 24, .... The least common multiple (LCM) of two numbers is the smallest number (not zero) that is a multiple of both.

Test Data:
console.log(lcm_two_numbers(3,15));
console.log(lcm_two_numbers(10,15));
Output :
15
30

Explanation of L.C.M.:

Visual Presentation of L.C.M. of two numbers:

Sample Solution:

JavaScript Code:

// Define a function named lcm_two_numbers that calculates the least common multiple (LCM) of two numbers.
function lcm_two_numbers(x, y) {
    // Check if both x and y are of type number, if not, return false.
    if ((typeof x !== 'number') || (typeof y !== 'number')) 
        return false;
    // Calculate the LCM using the formula: LCM(x, y) = |x * y| / GCD(x, y).
    return (!x || !y) ? 0 : Math.abs((x * y) / gcd_two_numbers(x, y));
}

// Define a function named gcd_two_numbers that calculates the greatest common divisor (GCD) of two numbers.
function gcd_two_numbers(x, y) {
    // Take the absolute values of x and y to ensure positivity.
    x = Math.abs(x);
    y = Math.abs(y);
    // Use the Euclidean algorithm to find the GCD.
    while(y) {
        var t = y;
        y = x % y;
        x = t;
    }
    // Return the GCD, which is stored in x after the loop.
    return x;
}

// Output the LCM of 3 and 15 to the console.
console.log(lcm_two_numbers(3, 15));
// Output the LCM of 10 and 15 to the console.
console.log(lcm_two_numbers(10, 15));

Output:

15
30

Flowchart:

Live Demo:

See the Pen javascript-math-exercise-10 by w3resource (@w3resource) on CodePen.

For more Practice: Solve these Related Problems:

• Write a JavaScript function that calculates the LCM of two numbers using their GCD.
• Write a JavaScript function that computes the LCM iteratively without recursion.
• Write a JavaScript function that calculates the LCM by first decomposing numbers into their prime factors.
• Write a JavaScript function that finds the LCM of two numbers and handles edge cases such as inputs of zero.

Go to:

• JavaScript Math and Numbers Exercises Home ↩
• JavaScript Exercises Home ↩

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