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Thought-Process to Discover Knowledge

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Books and other education websites provide "matter-of-fact" knowledge. Instead, nubtrek provides a thought-process to discover knowledge.

In each of the topic, the outline of the thought-process, for that topic, is provided for learners and educators.

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mathsDivisibility in Whole NumbersHighest Common Factor

### Co-prime Numbers

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What are the factors of 10 and 21?

• factors of 10 are 1,2,5,10
• factors of 21 are 1, 3, 7, 21
• both the above
• both the above

The answer is "both the above".

Factors of 10 are 1,2,5,10

Factors of 21 are 1, 3, 7, 21.

Factors of 6 are 1, 2, 3, 6.

Comparing the factors of 10 and 21, we find that they do not have any common factors, other than 1.

Comparing factors of 10 and 6, we find that they have a common factor 2.

10 and 21 are called "co-prime numbers".

10 and 6 are not co-prime numbers, as they share 2 as the common-factor.

Similarly, 6 and 21 are not co-prime numbers, as they share 3 as the common-factor.

Which of the following is a meaning for the prefix "co"?

• perform or work
• together and mutually
• together and mutually

The answer is "together and mutually".

What is the term used to refer to numbers that do not have a common factor?

• Pronunciation : Say the answer once

Co-prime Numbers : Two or more numbers without any common factor, other than 1, are called co-prime numbers.

Are 7 and 7 co-prime numbers?

• yes. 7 is a prime number
• no. They have a common factor 7
• no. They have a common factor 7

The answer is "no". They have a common factor 7.

Are 21 and 10 co-prime numbers?

• Yes, they do not have a common factor
• Yes, they do not have a common factor
• No, they have 1 as common factor

The answer is "Yes, they do not have a common factor".

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