CBSE Class 6 Maths Advanced Knowing Our Numbers Very Short Answer Questions Set 01

Very Short Answer Questions

Question 1. Fill in the blank: Smallest natural number is ______.
Answer:
The smallest natural number is 1.
In simple words: Counting starts from 1, so 1 is the first natural number.

Teacher's Note:
1. Natural numbers are 1, 2, 3, ...
2. 0 is a whole number but not a natural number.

Question 2. Fill in the blank: 1 crore = _________ lakh.
Answer:
1 crore = 1,00,00,000 and 1 lakh = 1,00,000, so 1 crore = 100 lakh.
In simple words: A hundred lakhs make one crore.

Teacher's Note:
1. Divide 1,00,00,000 by 1,00,000.
2. Learn: 1 lakh = 100 thousand and 1 crore = 100 lakh.

Question 3. Fill in the blank: The smallest 4-digit number with four different digits is ________.
Answer:
The smallest digit 1 goes first (0 cannot be first), then 0, then 2, then 3.
The number is 1023.
In simple words: Start with 1, then use the smallest remaining digits in order.

Teacher's Note:
1. The leading digit cannot be 0.
2. All four digits must be different, so 1000 or 1002 do not qualify.

Question 4. Fill in the blank: The total number of 4 digit number is ________
Answer:
Smallest 4-digit number = 1000 and greatest = 9999.
Count = 9999 − 1000 + 1 = 9000.
In simple words: There are nine thousand numbers from 1000 to 9999.

Teacher's Note:
1. Count = last − first + 1.
2. Do not forget to add 1.

Question 5. Fill in the blank: 564 when estimated to the nearest hundred is __________.
Answer:
The tens digit is 6, which is 5 or more, so the hundreds digit 5 goes up to 6.
564 rounds to 600.
In simple words: Round up because the tens digit is at least 5.

Teacher's Note:
1. Look at the digit just right of the place you are rounding to.
2. Then change the lower digits to zeros.

Question 6. Fill in the blank: 1678 when estimated to the nearest thousand is __________.
Answer:
The hundreds digit is 6, so round up: the thousands digit 1 becomes 2.
1678 rounds to 2000.
In simple words: Hundreds digit 6 pushes 1678 up to 2000.

Teacher's Note:
1. For thousands, check the hundreds digit.
2. A digit of 5 or more rounds up.

Question 7. Fill in the blank: 100 m = ___ cm
Answer:
1 m = 100 cm.
100 m = 100 × 100 cm = 10000 cm.
In simple words: Multiply by 100 to change metres to centimetres.

Teacher's Note:
1. Going from a bigger unit to a smaller one, multiply.
2. Write the zeros carefully.

Question 8. Fill in the blank: 650 km = ____ m
Answer:
1 km = 1000 m.
650 km = 650 × 1000 m = 650000 m (6,50,000 m).
In simple words: Multiply by 1000 to change kilometres to metres.

Teacher's Note:
1. Add three zeros to 650.
2. Indian grouping: 6,50,000.

Question 9. Fill in the blank: Which symbols are never repeated ____
Answer:
In Roman numerals the symbols V, L and D are never repeated.
Only I, X, C and M can be repeated, up to three times.
In simple words: V, L and D can each appear only once in a row.

Teacher's Note:
1. Think: 5, 50 and 500 can be made by other symbols, so no repeat is needed.
2. VV would just be X.

Question 10. Fill in the blank: The predecessor of XI is the whole number ___
Answer:
XI = 11 and its predecessor is 11 − 1 = 10 (X).
In simple words: One less than 11 is 10.

Teacher's Note:
1. Convert the Roman numeral to a number first.
2. The predecessor is always 1 less.

Question 11. State True or False: 99999 just comes before 1000000.
Answer:
False. The number just before 1000000 is 999999. 99999 comes just before 100000.
In simple words: 999999 + 1 = 1000000, not 99999 + 1.

Teacher's Note:
1. Count the digits: 1000000 has 7 digits, so its predecessor has 6 nines.
2. The predecessor of 1 followed by zeros is all nines.

Question 12. State True or False: The successor of the greatest 5-digit number is 100000.
Answer:
True. The greatest 5-digit number is 99999 and 99999 + 1 = 100000.
In simple words: Adding 1 to 99999 gives the smallest 6-digit number.

Teacher's Note:
1. The successor of the greatest n-digit number is the smallest (n + 1)-digit number.
2. 100000 is one lakh.

Question 13. State True or False: The difference in the face value and the place value of 5 in 85419 is 85414.
Answer:
False. In 85419 the digit 5 has face value 5 and place value 5000.
The difference is 5000 − 5 = 4995, not 85414.
In simple words: The difference is just 4995.

Teacher's Note:
1. Face value is the digit itself.
2. Place value = digit × value of its place.

Question 14. State True or False: 100 lakhs make a million.
Answer:
False. 100 lakh = 1 crore = 10 million.
A million equals 10 lakh.
In simple words: A million is 10 lakh, not 100 lakh.

Teacher's Note:
1. 1 million = 10,00,000.
2. Remember: 1 crore = 10 million.

Question 15. State True or False: The estimated value of 46,530 to the nearest hundred is 46500.
Answer:
True. The tens digit is 3 (less than 5), so the hundreds digit stays and the lower digits become zero: 46,500.
In simple words: Tens digit 3 means round down to 46,500.

Teacher's Note:
1. Check the tens digit when rounding to hundreds.
2. Less than 5 means keep the hundreds digit as it is.

Question 16. State True or False: The estimated value of 450 to the nearest hundred is 400.
Answer:
False. The tens digit is 5, so we round up: 450 rounds to 500.
In simple words: A tens digit of 5 rounds up to 500.

Teacher's Note:
1. A digit 5 always rounds up.
2. 450 is half-way, and the rule sends it up.

Question 17. State True or False: 1 km = 100 m.
Answer:
False. 1 km = 1000 m.
In simple words: A kilometre has 1000 metres.

Teacher's Note:
1. 'Kilo' means 1000.
2. 100 m is only a tenth of a kilometre.

Question 18. State True or False: 100 m = 1 cm.
Answer:
False. 1 m = 100 cm, so 100 cm = 1 m. And 100 m = 10000 cm.
In simple words: The statement has the units reversed.

Teacher's Note:
1. Compare the units: a metre is much longer than a centimetre.
2. Convert both sides to cm to check.

Question 19. State True or False: In Roman numeration, a symbol is not repeated more than three times.
Answer:
True. The symbols I, X, C and M can be repeated at most three times in a row, and V, L and D are never repeated.
In simple words: No symbol is written four times in a row.

Teacher's Note:
1. IIII is written IV; XXXX is written XL.
2. This rule keeps Roman numerals short.

Question 20. State True or False: In Roman numeration, if a symbol is repeated, its value is multiplied as many times as it occurs.
Answer:
False. When a symbol is repeated, its value is added as many times as it occurs (XX = 10 + 10 = 20).
In simple words: Repeated symbols are added, not multiplied.

Teacher's Note:
1. XXX = 10 + 10 + 10 = 30.
2. Multiplication is used only with a bar over a numeral (× 1000).

Question 21. State True or False: XXIX = 31.
Answer:
False. XXIX = 10 + 10 + (10 − 1) = 29.
In simple words: XXIX is 29; 31 is XXXI.

Teacher's Note:
1. IX is 9, not 11.
2. Break the numeral into XX and IX.

Question 22. State True or False: LXXIV = 74.
Answer:
True. LXXIV = 50 + 10 + 10 + (5 − 1) = 74.
In simple words: L, X, X and IV give 74.

Teacher's Note:
1. Split as L, XX, IV.
2. IV is 4 because I comes before V.

Question 23. State True or False: The number LIV is greater than LVI.
Answer:
LIV = 50 + (5 − 1) = 54 and LVI = 50 + 5 + 1 = 56.
54 is less than 56, so the statement is False.
In simple words: LIV is 54, which is smaller than LVI (56).

Teacher's Note:
1. IV is 4 but VI is 6.
2. The position of I decides subtraction or addition.

Question 24. Match the Column-I with Column-II.
Column-I: (A) 1 crore (B) 1 million (C) 100 thousand (D) 10 billion (E) 10 lakh
Column-II: (p) 1,000,000 (q) 100,000 (r) 10, 00,000 (s) 1,00,00,000 (t) 10,000,000,000
Answer:
(A) – (s): 1 crore = 1,00,00,000.
(B) – (p): 1 million = 1,000,000.
(C) – (q): 100 thousand = 100,000.
(D) – (t): 10 billion = 10,000,000,000.
(E) – (r): 10 lakh = 10,00,000.
In simple words: Each amount is written once in the Indian style and once in the International style.

Teacher's Note:
1. Note that 1 million and 10 lakh are the same number written in two systems.
2. Count the zeros in each to match.

Question 25. Match the Column-I with Column-II.
Column-I: (A) 9547999 comes just before (B) 287 round off to nearest ten (C) 15 round off to nearest hundred (D) I, X, C, M can be repeated maximum of (E) V, L, D are never
Column-II: (p) 0 (q) 3 times (r) 9548000 (s) repeated (t) 290
Answer:
(A) – (r): 9547999 + 1 = 9548000.
(B) – (t): 287 rounds to 290.
(C) – (p): 15 rounds to 0 at the nearest hundred (the tens digit 1 is less than 5).
(D) – (q): these symbols can be repeated at most 3 times.
(E) – (s): V, L and D are never repeated.
In simple words: Work out each item separately and then pair it.

Teacher's Note:
1. Rounding 15 to the nearest hundred gives 0.
2. Roman numeral rules appear in matching items often.