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Co-prime Numbers

Class 6 Maths · Chapter 5: Prime Time · NCERT Ganita Prakash section 5.3

Seekho

Do numbers co-prime hain jab unka ikloota common factor 1 ho. 8 aur 15 co-prime hain: 8 ke factors 1, 2, 4, 8 aur 15 ke 1, 3, 5, 15. Sirf 1 saajha hai.

common factor: only 1

Co-prime numbers ka prime hona zaroori nahi! 8 aur 15 dono composite hain, phir bhi co-prime hain. Aur 12 aur 18 co-prime nahi hain: dono 2, 3 aur 6 se bhaag hote hain.

Tenzin ki do fairy lights saath blink karti hain, phir ek har 4 second aur doosri har 9 second blink karti hai. Kyonki 4 aur 9 co-prime hain, wo agli baar 4 × 9 = 36 second baad saath blink karengi.

4 × 9 = 36

Explore: jode chhaanto. Kaun se co-prime hain?

  1. Har co-prime jode par tap karo.
  2. Do lights har 5 aur 6 second blink karti hain. Line par dhoondo agli baar kab saath blink karengi.

Yaad rakho

  • Co-prime: ikloota common factor 1. Prime hona zaroori nahi (8 aur 15).
  • Co-prime numbers ka pehla common multiple unka guna hai.

Quick check

Kaunsa joda co-prime hai?

  1. 6 and 9
  2. 10 and 15
  3. 9 and 16
  4. 12 and 20
Answer

9 and 16. 9 = 3 × 3 aur 16 = 2 × 2 × 2 × 2 ka 1 ke alawa koi factor saajha nahi.

Socho

Kya paas-paas ke do numbers, jaise 20 aur 21, hamesha co-prime hote hain? Kyon?

Ek answer

Haan. Agar 1 se bada koi number dono ko bhaag de, to wo unke antar ko bhi bhaag dega, jo 1 hai. 1 ko 1 se bada koi number bhaag nahi deta.

Practice

Teen levels (easy, medium, hard) ke naye sawaalon se practice karo, kuch hands-on, hints aur hal ke saath. Topic poora karne ke liye pichhle 5 mein se 4 sahi karo.