Question 1 - Page 130 - Digital Roots - Chapter 5 Class 8 - Number Play (Ganita Prakash)

Transcript

Question 1(i) - Page 130 Between the numbers 600 and 700, which numbers have the digital root: (i) 5 (ii) 7 (iii) 3To find these, find the first one, then just keep adding 9 to find the next ones! (i) Digital Root 5: Let’s check numbers after 600 For 601, Digital root is 6 + 1 = 7 For 602, Digital root is 6 + 2 = 8 For 603, Digital root is 6 + 3 = 9 For 604, Digital root is 6 + 4 = 10 → 1 + 0 = 1 For 605, Digital root is 6 + 5 = 11 → 1 + 1 = 2 For 606, Digital root is 6 + 6 = 12 → 1 + 2 = 3 For 607, Digital root is 6 + 7 = 13 → 1 + 3 = 4 For 608, Digital root is 6 + 8 = 14 → 1 + 4 = 5 ∴ The first one after 600 is 608 Next will be 608 + 9 = 617 and so on Thus, our sequence is 608, 617, 626, 635, 644... (ii) Digital Root 7: We notice that first one is 601 Next will be 601 + 9 = 610 and so on Thus, our sequence is 601, 610, 619, 628, 637... (iii) Digital Root 3: We notice that first one is 606 Next will be 606 + 9 = 615 and so on Thus, our sequence is 606, 615, 624, 633, 642...