Class 7 Computational Thinking & AI
Official CBSE Student Handbook curriculum with 240 interactive practice questions, algorithmic thinking puzzles, visual reasoning diagrams, and ethical AI case studies.
Large Numbers Around Us
Large Numbers Around Us develops algorithmic decomposition and constraint-based problem solving by exploring multi-digit number properties, place values, and cryptarithmetic puzzles.
Practice Questions (20)
Click an option to test your answer‘X’ is a 6-digit number formed using exactly three different digits. One of the digits appears once, another appears twice, and the third appears three times. When 2 lakhs (200,000) are added to ‘X’, the resulting number ‘Y’ is still a 6-digit number. What is the highest possible value of ‘Y’?
Hint: X cannot start with 8 or 9 because adding 200,000 would exceed 6 digits. Maximize X starting with 7.
What is the product of all the numbers on a telephone dial-pad (0 through 9)?
Hint: Don't forget the bottom center button on a phone dial-pad: 0!
Sam forms two different 6-digit numbers, X and Y, using digits from 0 to 9 without repetition. Exactly two digits are common between X and Y. • The digit 9 appears in the same position in both numbers • Y ends with 0, has only one even digit, and its digits are arranged in descending order • 6 is present in X, and the number of even digits on its left equals the number of even digits on its right If X is the largest possible number, what is the difference between X and Y?
Hint: Y is formed from odd digits in descending order ending with 0: 975310.
If each of the rows follows the same comparison theme: Row 1: (1, 8, 2) > (1, 8, 2) → ≤ 7 Row 2: (3, 5, 7) < (3, 5, 7) → ≤ 3 Row 3: (9, 6, 3) > (9, 6, 3) → ≤ 2 Row 4: (5, 0, 6) < (5, 6, 0) → ? What will come in place of '?'
Hint: Look at the first and middle digit bounds in each evaluation row.
In a place-value word reduction code: Crore − re → 00000 (5 zeros) Million − ion → 000 (3 zeros) Thousand − d → 00 (2 zeros) Billion − llion → 0000 (4 zeros) Lakh − kh → ?
Hint: 1 Lakh = 100,000 (5 zeros). 'kh' has 2 letters. 5 − 2 = 3 zeros.
Six number tokens are given: [2, 5, 8, 1, 4, 7]. Rearrange them to form a 6-digit number such that: • The difference between the first and last digits is as small as possible • The hundreds digit is double the thousands digit • No consecutive digits appear next to each other • All given tokens must be used exactly once How many different 6-digit numbers between 2 lakhs and 8 lakhs can be formed?
Hint: Pairs where Hundreds = 2 × Thousands: (1, 2), (2, 4), or (4, 8).
Two 5-digit numbers are formed using distinct digits from 0 to 9: Number 1: _ 1 _ 9 _ Number 2: _ 4 _ 6 _ No two consecutive digits of the number series are present in the same number. What is the maximum possible difference of the numbers formed?
Hint: Maximize the first number and minimize the second number while respecting non-consecutive digit rules.
A, B, C, D, and E each have a different number card among: One hundred (2 zeros), One thousand (3 zeros), Ten thousand (4 zeros), One lakh (5 zeros), and Ten lakhs (6 zeros). • C has an even number of zeros • A’s number has 2 zeros less than C’s number • D’s number has 4 zeros more than A’s number • The number of zeros in B is more than A but less than C Which number card does E have?
Hint: A = 2 zeros (100), B = 3 zeros (1,000), C = 4 zeros (10,000), D = 6 zeros (10,00,000). What is left for E?
4 friends: Alex, Bob, Calvin, and David have different professions (Doctor, Lawyer, Cricketer, Engineer) and salaries (₹40,000, ₹50,000, ₹60,000, ₹70,000): • The cricketer earns the highest (₹70,000) • Alex earns more than Bob; the doctor earns more than David (who is the engineer) • Bob is the lawyer, and neither Bob nor David earns ₹50,000 Which option shows the correct profession and salary of Calvin?
Hint: Cricketer earns ₹70,000. David is the Engineer at ₹40,000. Bob is Lawyer at ₹60,000.
The following are the clues to the 6-digit password of Nisha’s laptop: • 35 tens (350) • 31 thousands (31,000) • 25 ones (25) • 423 hundreds (42,300) • 14 ten thousands (140,000) What is Nisha’s password?
Hint: Sum: 140,000 + 42,300 + 31,000 + 350 + 25.
A 6-digit number has the form ABCDEF where each letter is a distinct digit from 1 to 6. If A > B > C and D < E < F, and the sum A + B + C = D + E + F = 11, which of the following is a possible value for the number?
Hint: Check the constraints: A > B > C and D < E < F with matching sum constraints.
In the Indian place value system, how many periods are there in a 9-digit number?
Hint: The periods are: Ones, Thousands, Lakhs, and Crores.
How many 5-digit numbers have the property that the product of their digits is 0?
Hint: Total 5-digit numbers minus 5-digit numbers with no zero digit (9 × 9 × 9 × 9 × 9).
If 1 Million = 10 Lakhs and 1 Billion = 100 Crores, how many Millions are equal to 2.5 Billions?
Hint: 1 Billion = 10⁹ and 1 Million = 10⁶. 1 Billion = 1,000 Millions.
A digital lock requires a 4-digit code. The code is an even number, the thousands digit is a prime number greater than 5, the hundreds digit is a perfect square, and the tens digit is 0. What is the code if all digits are distinct?
Hint: Thousands digit must be 7 (the only single-digit prime > 5).
Arrange the following numbers in descending order: P = 4 Crores 50 Lakhs Q = 45 Millions R = 405 Lakhs S = 4,500 Thousands
Hint: 1 Crore = 100 Lakhs, 1 Million = 10 Lakhs, 1 Thousand = 0.01 Lakh.
What is the smallest 7-digit number that can be formed using each of the digits 8, 0, 3, 5, 2, 9, 1 exactly once?
Hint: A 7-digit number cannot start with 0. Place the smallest non-zero digit first, then 0, then ascending.
In a cryptarithmetic puzzle: SEND + MORE = MONEY, what digit does 'M' represent?
Hint: The sum of two 4-digit numbers cannot exceed 19,998, so the leading digit of a 5-digit sum is always 1.
Rounding off 74,85,632 to the nearest Ten Thousands gives:
Hint: Look at the thousands digit (5). If it is 5 or more, round up the ten thousands digit.
A library has 12,45,600 books. If 3,78,950 books are issued and 1,24,300 new books are added, how many books are currently in the library?
Hint: Subtract the issued books from the initial count, then add the new arrivals.
The Thinking Spot: Columns of Numbers
Columns A, B, and C contain 3 numbers each. The number of times each number appears in all 3 columns combined equals its value (e.g. 2 appears twice, 3 appears thrice, 4 appears four times). Each column contains AT LEAST TWO different numbers.
Question: Which column has the highest sum?