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Question 13 - Figure it out - Page 63, 64 - Chapter 3 Class 7 - Finding Common Ground (Ganita Prakash II)
Last updated at January 23, 2026 by Teachoo
Figure it out - Page 63, 64
Class 7 (Ganita Prakash 1, 2 & old NCERT)
Chapter 3 Class 7 - Finding Common Ground (Ganita Prakash II)
- The Greatest of All
- Prime Factorisation
- Finding HCF using Prime Factorisation
- Figure it out - Page 54
- Least, but not Last!
- Finding LCM using Prime Factorisation
- Patterns, Properties, and a Pretty Procedure!
- Figure it out - Page 59
- Miscellenaous Questions on HCF, LCM
- Efficient Procedures for HCF and LCM
- Property Involving both the HCF and the LCM
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Figure it out - Page 63, 64
Transcript
Question 13 Here is a problem posed by the ancient Indian Mathematician Mahaviracharya (850 C.E.). Add together 8/15, 1/20, 7/36, 11/63, and 1/21. What do you get? How can we find this sum efficiently?We need to add 8/15+1/20+7/36+11/63+1/21 To add this, we need to make denominator same Now, Common Denominator = LCM of 15, 20, 36, 63, 21 Finding LCM 15, 20, 36, 63, 21 15, 10, 18, 63, 21 15, 5, 9, 63, 21 5, 5, 3, 21, 7 5, 5, 1, 7, 7 1, 1, 1, 7, 7 1, 1, 1, 1, 1 Convert fraction to denominator 1260: 8/15=(8×84)/1260=672/1260 1/20=(1×63)/1260=63/1260 7/36=(7×35)/1260=245/1260 11/63=(11×20)/1260=220/1260 1/21=(1×60)/1260=60/1260 Finding sum: Thus, our sum becomes 8/15+1/20+7/36+11/63+1/21 = 672/1260+63/1260+245/1260+220/1260+60/1260 = (672+63+245+220+60)/1260 = 𝟏𝟐𝟔𝟎/𝟏𝟐𝟔𝟎 = 1 Thus, the sum is 𝟏. = 𝟏𝟐𝟔𝟎/𝟏𝟐𝟔𝟎 = 1 Thus, the sum is 𝟏.
