Number Play — Quiz

Q1. In the heights-and-neighbours puzzle, can the children rearrange themselves so that the two children standing at the ends both say '2'?

• A. Yes, if the end children are the tallest of all.
• B. Yes, if both end children stand on tiptoe.
• C. No, because each end child has only one neighbour.
• D. No, because '2' is the largest number a child can say.

Q2. When can a line of children be arranged so that every child in the line says '0'?

• A. When all the children have the same height.
• B. When the children stand in ascending order of height.
• C. When only the end children are tall.
• D. Never, because at least one child must say '1'.

Q3. Five children of different heights stand in a line. They are arranged in ascending order of height. What numbers will they say (from left to right)?

• A. 0, 1, 1, 1, 1
• B. 1, 0, 1, 0, 1
• C. 0, 0, 0, 0, 0
• D. 1, 1, 1, 1, 0

Q4. In a supercell table with all numbers different, can the cell holding the smallest number ever be a supercell?

• A. Yes, if the smallest number is at the edge.
• B. Yes, if the smallest number is odd.
• C. No, because every other number in the table is bigger.
• D. Only when the table has exactly 9 cells.

Q5. Out of the 9 numbers in the Figure-it-Out grid 6828, 670, 9435, 3780, 3708, 7308, 8000, 5583, 52 how many supercells are there?

• A. 3
• B. 4
• C. 5
• D. 6

Q6. On a number line showing 9996, 9997 and the next few positions, what whole number comes immediately after 9999?

• A. 9990
• B. 10000
• C. 9991
• D. 99100

Q7. How many 5-digit whole numbers are there in our number system?

• A. 9000
• B. 10000
• C. 90000
• D. 99999

Q8. What is the smallest whole number whose digit sum is 14?

• A. 49
• B. 68
• C. 77
• D. 59

Q9. What is the largest 5-digit whole number whose digit sum is exactly 14?

• A. 95000
• B. 59000
• C. 91400
• D. 99500

Q10. How many 3-digit palindromic numbers can be formed using only the digits 1, 2 and 3 (with repetition allowed)?

• A. 3
• B. 6
• C. 9
• D. 27

Q11. Following the chapter's 'reverse-and-add' procedure starting with 48: 48 + 84 = 132, then 132 + 231 = ___. Which palindrome do we reach?

• A. 262
• B. 353
• C. 484
• D. 363

Q12. In the Kaprekar process starting with 6382: A = largest = 8632, B = smallest = 2368. What is C = A − B?

• A. 6264
• B. 6262
• C. 5264
• D. 4176

Q13. On a 12-hour clock, the time now is 10:01. After how many minutes will the clock next show a palindromic time?

• A. 10 minutes
• B. 70 minutes
• C. 110 minutes
• D. 120 minutes

Q14. Apply the Collatz rule starting from 100. The first six terms are

• A. 100, 50, 25, 76, 38, 19
• B. 100, 50, 25, 75, 38, 19
• C. 100, 200, 100, 50, 25, 76
• D. 100, 51, 26, 13, 40, 20

Q15. Sheetal is in Grade 6 and says she has spent around 13,000 hours in school till now. About how many years of school (assuming roughly 1,300 hours per year) does this estimate suggest?

• A. About 3 years
• B. About 10 years
• C. About 20 years
• D. About 50 years