Knowing Our Numbers

Short Answer Questions(SAQs)

What is BODMAS?

The BODMAS acronym stands for brackets, orders, division, multiplication, addition, subtraction. It defines the sequence of operations to solve an expression correctly.

What are Roman numerals?

Roman numerals are the symbolic representation of numbers that do not follow a place value system. They use letters like I, V, X, L, C, D and M to represent numbers.

What are real numbers?

Real numbers are numbers that include both rational and irrational numbers. They can be represented on the number line and include whole numbers, integers, fractions, and surds.

MCQs

1. What is the value of the Roman numeral 'XL'?

(a) 10

(b) 40

(c) 50

(d) 90

► (b) XL represents 40 as X (10) before L (50) implies subtraction: 50 - 10 = 40.

2. Which of the following is the correct BODMAS order?

(a) Brackets, Orders, Division, Multiplication, Addition, Subtraction

(b) Brackets, Orders, Multiplication, Division, Addition, Subtraction

(c) Orders, Brackets, Division, Multiplication, Addition, Subtraction

(d) Brackets, Orders, Addition, Multiplication, Subtraction, Division

► (a) The BODMAS rule follows Brackets → Orders → Division → Multiplication → Addition → Subtraction.

3. Which of the following is NOT a real number?

(a) 75

(b) π

(c) √2

(d) None of the above

► (d) All of the options are real numbers, including irrational numbers like π and √2.

4. What comes after 99,999?

(a) 1,00,000

(b) 99,100

(c) 1,000

(d) 10,000

► (a) 1,00,000 is the next number after 99,999.

5. What is the Roman numeral for 90?

(a) XC

(b) LXXXX

(c) IC

(d) XXC

► (a) XC represents 90, as X (10) before C (100) means 100 - 10 = 90.

6. Which symbol is used for 1000 in Roman numerals?

(a) M

(b) D

(c) C

(d) X

► (a) M represents 1000 in Roman numerals.

7. What is the place value of 5 in the number 56,789?

(a) 5

(b) 50

(c) 5,000

(d) 50,000

► (d) The place value of 5 in 56,789 is 50,000.

8. Which is the largest 5-digit number?

(a) 99,999

(b) 9,999

(c) 100,000

(d) 1,00,001

► (a) 99,999 is the largest 5-digit number.

9. Convert the Roman numeral 'D' into a number.

(a) 50

(b) 100

(c) 500

(d) 1000

► (c) 'D' represents 500 in Roman numerals.

10. Which number system does NOT use the concept of zero?

(a) Roman

(b) Hindu-Arabic

(c) Decimal

(d) Binary

► (a) The Roman numeral system does not use zero.

11. Which digit is in the thousands place in 78,902?

(a) 7

(b) 8

(c) 9

(d) 0

► (b) 8 is in the thousands place in 78,902.

12. Find the difference between the place values of 6 and 2 in 6,32,671.

(a) 6,00,000

(b) 5,99,800

(c) 5,99,900

(d) 6,00,100

► (c) Place value of 6 is 6,00,000 and 2 is 100. Difference is 5,99,900.

13. Which of the following is an irrational number?

(a) 89

(b) 0.75

(c) √2

(d) 1.2

► (c) √2 is an irrational number because it cannot be expressed as a fraction.

14. Which of these is a 7-digit number?

(a) 10,00,000

(b) 9,99,999

(c) 1,00,000

(d) 1,000

► (a) 10,00,000 is a 7-digit number.

15. Which number is one less than one lakh?

(a) 99,999

(b) 1,00,001

(c) 1,00,000

(d) 99,900

► (a) 99,999 is one less than 1,00,000.

16. What is the expanded form of 6,105?

(a) 6,000 + 100 + 5

(b) 6,000 + 10 + 5

(c) 6,000 + 100 + 50

(d) 6,000 + 1 + 5

► (b) The expanded form is 6,000 + 100 + 5.

17. What is the correct Roman numeral for 2024?

(a) MMXXIV

(b) MCMXXIV

(c) MMCDXXIV

(d) MMCXXIV

► (a) 2024 in Roman numerals is MMXXIV.

18. What is the smallest 5-digit number?

(a) 9,999

(b) 10,000

(c) 1,000

(d) 11,111

► (b) 10,000 is the smallest 5-digit number.