Short Trick to find LCM & HCF of fractions

Duration: 9 min

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This educational video, presented by Yash Jain from Knowledge Gate Eduventures, provides a comprehensive lesson on finding the Least Common Multiple (LCM) and Highest Common Factor (HCF) of fractions. The lecture begins with an introduction to the topic, followed by the presentation of the core formulas. The LCM of fractions is defined as the LCM of the numerators divided by the HCF of the denominators, while the HCF of fractions is the HCF of the numerators divided by the LCM of the denominators. The instructor then demonstrates these concepts through a series of worked examples. The first example calculates the LCM of the fractions 7 1/2, 6 1/4, and 35/8, which involves converting mixed numbers to improper fractions (15/2, 25/4, 35/8), finding the LCM of the numerators (15, 25, 35) as 525, and the HCF of the denominators (2, 4, 8) as 2, resulting in an LCM of 525/2. The second example calculates the HCF of 3/2, 9/8, and 15/16, which involves finding the HCF of the numerators (3, 9, 15) as 3 and the LCM of the denominators (2, 8, 16) as 16, resulting in an HCF of 3/16. The final example calculates the HCF of 28/15, 98/35, and 56/25, yielding a result of 14/525. The video concludes with a 'Thanks for Watching' screen.

Chapters

  1. 0:00 – 2:00 00:00-02:00

    The video opens with a title card displaying 'LCM & HCF' against a digital, data-stream background. It then transitions to a classroom-style animation with a female teacher character and a male instructor, Yash Jain, in a picture-in-picture window. The main topic is introduced as 'Least Common Multiple (LCM)' and 'Highest Common Factor (HCF)'. The instructor begins to explain the concept of LCM of fractions, writing the formula on a digital whiteboard: LCM of (a/b, c/d, e/f) = LCM(a, c, e) / HCF(b, d, f). The on-screen text '9. LCM of fractions' is visible at the top of the whiteboard.

  2. 2:00 – 5:00 02:00-05:00

    The instructor continues to explain the concept of LCM of fractions, writing the formula LCM(a/b, c/d, e/f) = LCM(a, c, e) / HCF(b, d, f) on the whiteboard. He then transitions to the concept of HCF of fractions, writing the formula HCF(a/b, c/d, e/f) = HCF(a, c, e) / LCM(b, d, f). The on-screen text '9. LCM of fractions' remains visible. The instructor uses red ink to highlight the key components of the formulas, emphasizing the relationship between the LCM and HCF of the numerators and denominators. The copyright notice for 'KNOWLEDGE GATE EDUVENTURES' is visible at the bottom of the screen.

  3. 5:00 – 8:51 05:00-08:51

    The video presents a worked example for LCM of fractions: LCM(7 1/2, 6 1/4, 35/8). The instructor converts the mixed numbers to improper fractions: 15/2, 25/4, and 35/8. He then applies the formula, calculating LCM(15, 25, 35) = 525 and HCF(2, 4, 8) = 2, resulting in an LCM of 525/2. The next example is HCF(3/2, 9/8, 15/16). He calculates HCF(3, 9, 15) = 3 and LCM(2, 8, 16) = 16, resulting in an HCF of 3/16. The final example is HCF(28/15, 98/35, 56/25). He calculates HCF(28, 98, 56) = 14 and LCM(15, 35, 25) = 525, resulting in an HCF of 14/525. The video ends with a 'Thanks for Watching' screen.

The video provides a clear, step-by-step tutorial on calculating the LCM and HCF of fractions. It begins by establishing the fundamental formulas, which are the cornerstone of the lesson. The instructor then applies these formulas to three distinct problems, each demonstrating a different aspect of the calculation process, such as handling mixed numbers and simplifying the final result. The consistent use of a digital whiteboard for writing and the clear, methodical approach make the complex topic accessible for students preparing for competitive exams.