Question 1 - Playing with Digits - Chapter 3 Class 6 - Number Play (Ganita Prakash)

Transcript

Question 1 (a) Digit sum 14 a. Write other numbers whose digits add up to 14. We can get digit sum 14 in these numbers 59, 77, 86, 257, 329, 419, 860, 1535, and 9050. Question 1 (b) Digit sum 14 b. What is the smallest number whose digit sum is 14? Now, we cannot have digit sum 14 using a 1-digit number So, smallest number should be a 2-digit number Now, smallest 2-digit number should have smallest ten’s digit If we write 5 + 9 = 14, Then we get smallest ten’s digit Thus, smallest number is 59. Question 1 (c) Digit sum 14 c. What is the largest 5-digit whose digit sum is 14? To make the largest number, we should place the largest possible digits in the highest place values (the leftmost digits). Starting with 9, the remaining four digits must sum to 5 (14 - 9 = 5). Placing a 5 in the next spot leaves a sum of 0 for the rest, So, we can put 0 as last three digits Thus, largest 5-digit number is 95,000. Question 1 (d) Digit sum 14 d. How big a number can you form having the digit sum of 14? Can you make an even bigger number? There is no limit to how a big number can be We saw largest 5-digit number as 95,000 Now, we can add as many zero at the end as possible to make larger and larger number. Like 95,00,000 9,50,00,000 9,50,00,00,00,00,000 Thus, we can always make a bigger number