Question 1

Q1: The Thoughtful Thousands only has a +1000 button. How many times should it be pressed to show: (a) Three thousand? 3 times (b) 10,000 ? (c) Fifty thre...

Accepted Answer

Solution: To find the number of times the +1000 button should be pressed, we divide the target number by 1000. (b) $10,000 \div 1000 = 10$ times. (c) Fifty three thousand = $53,000$. $53,000 \div 1000 = 53$ times. (d) $90,000 \div 1000 = 90$ times. (e) One Lakh = $1,00,000$. $1,00,000 \div 1000 = 10...

Question 2

Q2: The Tedious Tens only has a +10 button. How many times should it be pressed to show: (a) Five hundred?  (b) 780 ?  (c) 1000?  (d) 3700?  (e) 10,000?...

Accepted Answer

Solution: To find the number of times the +10 button should be pressed, we divide the target number by 10. (a) Five hundred = 500. $500 \div 10 = 50$ times. (b) $780 \div 10 = 78$ times. (c) $1000 \div 10 = 100$ times. (d) $3700 \div 10 = 370$ times. (e) $10,000 \div 10 = 1000$ times. (f) One lakh =...

Question 3

Q3: The Handy Hundreds only has a +100 button. How many times should it be pressed to show: (a) Four hundred?  (b) 3,700 ?  (c) 10,000 ?  (d) Fifty three...

Accepted Answer

Solution: To find the number of times the +100 button should be pressed, we divide the target number by 100. (a) Four hundred = 400. $400 \div 100 = 4$ times. (b) $3,700 \div 100 = 37$ times. (c) $10,000 \div 100 = 100$ times. (d) Fifty three thousand = $53,000$. $53,000 \div 100 = 530$ times. (e) $...

Question 4

Q4: Find a different way to get 5072 and write an expression for the same.

Accepted Answer

Given: Two ways to get 5072 are shown: (a) $(50 	imes 100)+(7 	imes 10)+(2 	imes 1)=5072$ (b) $(3 	imes 1000)+(20 	imes 100)+(72 	imes 1)=5072$ To Find: A different way to get 5072. Solution: We can break down the number 5072 in many ways. One different way is to use the standard place value e...

Question 5

Q1: What if a person ate 3 varieties of rice every day? Will they be able to taste all the lakh varieties in a 100 year lifetime? Find out.

Accepted Answer

Given: - Number of rice varieties = 1 lakh = 1,00,000 - Varieties tasted per day = 3 - Lifetime = 100 years To Find: Whether a person can taste all 1,00,000 varieties in a 100-year lifetime. Solution: First, we calculate the total number of days in a 100-year lifetime, ignoring leap years. Number of...

Question 6

Q2: Choose a number for $y$. How close to one lakh is the number of days in $y$ years, for the $y$ of your choice?

Accepted Answer

Given: - The number of days in our lifetime is given by the expression $365 	imes y$, where $y$ is the number of years. - We need to find how close this is to one lakh (1,00,000). Let: Let us choose $y = 274$ years (as hinted in the text). Solution: We calculate the total number of days for $y = 27...

Question 7

Q1: According to the 2011 Census, the population of the town of Chintamani was about 75,000 . How much less than one lakh is 75,000 ?

Accepted Answer

Given: - Population of Chintamani in 2011 = 75,000 - One lakh = 1,00,000 To Find: How much less than one lakh is 75,000. Solution: We need to find the difference between one lakh and 75,000. Difference = $1,00,000 - 75,000$ Difference = 25,000 Final Answer: 75,000 is 25,000 less than one lakh.

Question 8

Q2: The estimated population of Chintamani in the year 2024 is $1,06,000$. How much more than one lakh is $1,06,000$ ?

Accepted Answer

Given: - Estimated population of Chintamani in 2024 = 1,06,000 - One lakh = 1,00,000 To Find: How much more than one lakh is 1,06,000. Solution: We need to find the difference between 1,06,000 and one lakh. Difference = $1,06,000 - 1,00,000$ Difference = 6,000 Final Answer: 1,06,000 is 6,000 more th...

Question 9

Q3: By how much did the population of Chintamani increase from 2011 to 2024?

Accepted Answer

Given: - Population in 2011 = 75,000 - Population in 2024 = 1,06,000 To Find: The increase in population from 2011 to 2024. Solution: We subtract the 2011 population from the 2024 population. Increase = Population in 2024 - Population in 2011 Increase = $1,06,000 - 75,000$ Increase = 31,000 Final An...

Question 10

Q1: For each number given below, write expressions for at least two different ways to obtain the number through button clicks. Think like Chitti and be cr...

Accepted Answer

Solution: Here are two different expressions for each number: (a) 8300 1. $(8 	imes 1000) + (3 	imes 100)$ 2. $(83 	imes 100)$ (b) 40629 1. $(4 	imes 10000) + (6 	imes 100) + (2 	imes 10) + (9 	imes 1)$ 2. $(40 	imes 1000) + (62 	imes 10) + (9 	imes 1)$ (c) 56354 1. $(5 	imes 10000) + (6...

Question 11

Q2: Creative Chitti has some questions for you- (a) You have to make exactly 30 button presses. What is the largest 3-digit number you can make? What is t...

Accepted Answer

Solution: (a) Largest and Smallest 3-digit number with 30 clicks Let the number of presses for +100, +10, and +1 be $a, b, c$ respectively.  We are given $a+b+c=30$.  The number formed is $N = 100a + 10b + c$. To find the largest 3-digit number: We need to maximize $N = 100a + 10b + c$ subject to $a...

Question 12

Q1: Look at the picture on the right. Somu is 1 metre tall. If each floor is about four times his height, what is the approximate height of the building?

Accepted Answer

Given: - Somu's height = 1 metre - Height of each floor = 4 times Somu's height - The building in the picture has a ground floor and 10 upper floors, making a total of 11 floors. To Find: The approximate height of the building. Solution: First, we calculate the height of a single floor. Height of on...

Question 13

Q2: Which is taller - The Statue of Unity or this building? How much taller?

Accepted Answer

Given: - Height of the Statue of Unity = 180 metres - Approximate height of the building = 44 metres To Find: Which is taller and by how much. Solution: First, we compare the heights. $180 	ext{ m} > 44 	ext{ m}$. So, the Statue of Unity is taller than the building. Next, we find the difference in...

Question 14

Q3: How much taller is the Kunchikal waterfall than Somu's building?

Accepted Answer

Given: - Height of Kunchikal waterfall = 450 metres - Approximate height of Somu's building = 44 metres To Find: How much taller the waterfall is than the building. Solution: We find the difference in their heights. Difference = Height of waterfall - Height of building Difference = $450 	ext{ m} -...

Question 15

Q4: How many floors should Somu's building have to be as high as the waterfall?

Accepted Answer

Given: - Height of Kunchikal waterfall = 450 metres - Height of one floor of Somu's building = 4 metres To Find: The number of floors required to match the waterfall's height. Solution: We divide the total height of the waterfall by the height of a single floor. Number of floors = Total height $\div...

Question 16

Q1: Write each of the numbers given below in words: (a) $3,00,600$ (b) $5,04,085$ (c) $27,30,000$ (d) $70,53,138$

Accepted Answer

Solution: (a) $3,00,600$ is written as: Three lakh six hundred. (b) $5,04,085$ is written as: Five lakh four thousand eighty-five. (c) $27,30,000$ is written as: Twenty-seven lakh thirty thousand. (d) $70,53,138$ is written as: Seventy lakh fifty-three thousand one hundred thirty-eight.

Question 17

Q2: Write the corresponding number in the Indian place value system for each of the following: (a) One lakh twenty three thousand four hundred and fifty s...

Accepted Answer

Solution: (a) One lakh twenty three thousand four hundred and fifty six: $1,23,456$ (b) Four lakh seven thousand seven hundred and four: $4,07,704$ (c) Fifty lakhs five thousand and fifty: $50,05,050$ (d) Ten lakhs two hundred and thirty five: $10,00,235$

NCERT Solutions