NCERT Solutions
Class 10 - Mathematics - Chapter 1: REAL NUMBERS - EXERCISE 1.1
Question 4

Question. 4

Given that HCF(306, 657) = 9, find LCM(306, 657).

Answer:

22338

Detailed Answer with Explanation:

We are given two numbers, 306 and 657, and their HCF (Highest Common Factor) is 9.

There is a standard relation between LCM and HCF of two numbers:

\( \text{LCM} \times \text{HCF} = \text{product of the two numbers} \)

We can use this relation to find the LCM when the HCF and the two numbers are known.

Step 1: Write the relation for our numbers

Here, the numbers are 306 and 657, and

\( \text{HCF} = 9 \)

So,

\( \text{LCM}(306, 657) \times 9 = 306 \times 657 \)

We want to find \( \text{LCM}(306, 657) \).

Step 2: Rearrange the formula to make LCM the subject

From

\( \text{LCM} \times 9 = 306 \times 657 \)

we get

\( \text{LCM}(306, 657) = \dfrac{306 \times 657}{9} \)

Step 3: Simplify the fraction

It is easier to first divide 306 by 9, instead of multiplying first and then dividing.

Compute:

\( 306 \div 9 = 34 \)

So the expression becomes:

\( \text{LCM}(306, 657) = 34 \times 657 \)

Step 4: Multiply 34 and 657

We multiply step by step using simple break-up.

Write 34 as \( 30 + 4 \).

First, calculate \( 657 \times 30 \).

\( 657 \times 30 = 657 \times 3 \times 10 \)

\( 657 \times 3 = 1971 \)

So,

\( 657 \times 30 = 1971 \times 10 = 19710 \)

Next, calculate \( 657 \times 4 \).

\( 657 \times 4 = 2628 \)

Now add these two results:

\( 19710 + 2628 = 22338 \)

So,

\( 34 \times 657 = 22338 \)

Step 5: Conclude the value of LCM

We have found:

\( \text{LCM}(306, 657) = 22338 \)

Therefore, the LCM of 306 and 657 is 22338.

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