3. A Story of Numbers – Worksheet Solutions

1. MCQs

Q1: In the Roman numeral system, what number does MCMXLIV represent?
a) 
1944
b) 1444
c) 1949
d) 1494
Answer: a) 1944

Q2: If the base of a number system is 7, what is the 4th landmark number after 1?
a)
 28
b) 49
c) 343
d) 7
Answer: b) 49

Q3: Symbolis representation for which number?

a) 60
b) 
360
c) 
3600
d) 
any multiple of 60

Answer: a) 60

Q4: In a base-8 system, what is the value of the number 345 (base 8) in base-10?
a)
 229
b) 228
c) 230
d) 231
Answer: a) 229

Q5: In a base-5 system, the third landmark number after 1 is:
a)
 15
b) 25
c) 20
d) 30
Answer: b) 25

2. True / False

Q1: The Bakhshali manuscript contains the earliest known example of the number zero written as a dot. 

Ans: True

Q2: Roman numerals can easily be used for multiplication and division. 

Ans: False

Q3:The Gumulgal people counted numbers in groups of 2. 

Ans: True

Q4: The Lebombo bone is believed to be younger than the Ishango bone. 

Ans: False

Q5: In the Egyptian number system, each landmark number is 10 times the previous one. 

Ans: True

3. Fill in the blanks

Q1: The ancient counting device made of a frame with rods and beads is called an __________.
Ans: abacus

Q2: In the Roman numeral system, C represents the number __________.
Ans: 100

Q3: The Roman numeral for 1000 is represented as __________.
Ans: M

Q4: The Roman numeral for 50 is represented as __________.
Ans: L

Q5: A number system in which each landmark number is obtained by multiplying the previous landmark number by a fixed number n is called a __________ system.
Ans: base-n

4. Answer the following Questions

Q1. Represent the following numbers in the Roman system.

(i) 1444

Ans: Break it down:
1000 + 400 + 40 + 4 = M + CD + XL + IV

Answer: MCDXLIV

(ii) 1867

Ans: Break it down:
1000 + 800 + 60 + 7 = M + DCCC + LX + VII

Answer: MDCCCLXVII

(iii) 2539

Ans: Break it down:
2000 + 500 + 30 + 9 = MM + D + XXX + IX

Answer: MMDXXXIX

(iv) 948

Ans: Break it down:
900 + 40 + 8 = CM + XL + VIII

Answer: CMXLVIII

Q2. Consider the extension of the Gumulgal number system beyond 6 in the same way of counting by 2s. Come up with ways of performing the different arithmetic operations (+, –, ×, ÷) for numbers occurring in this system, without using Hindu numerals. Use this to evaluate the following:

(i) (ukasar-ukasar-ukasar-urapon) + (ukasar-urapon)

Ans:Break it down:
(2 + 2 + 2 + 1) + (2 + 1) = 7 + 3 = 10

(Gumulgal): ukasar-ukasar-ukasar-ukasar-ukasar
(= ukasar repeated 5 times → 2×5 = 10)

(ii) (ukasar-ukasar-ukasar-ukasar-urapon) − (ukasar-ukasar-urapon)

Ans: Break it down:
(2+2+2+2+1) − (2+2+1) = 9 − 5 = 4

(Gumulgal): ukasar-ukasar
(= 2 + 2 = 4)

(iii) (ukasar-ukasar-ukasar) × (ukasar-urapon)

Ans: Break it down:
(2+2+2) × (2+1) = 6 × 3 = 18

(Gumulgal): (ukasar repeated 9 times)
= 9×2 = 18 → write ukasar nine times:

ukasar-ukasar-ukasar-ukasar-ukasar-ukasar-ukasar-ukasar-ukasar

(iv) (ukasar-ukasar-ukasar-ukasar-ukasar-ukasar) ÷ (ukasar-ukasar)

Break it down:
(2+2+2+2+2+2) ÷ (2+2) = 12 ÷ 4 = 3

(Gumulgal): ukasar-urapon
(= 3)

Q3: Represent the following numbers in the Egyptian system:

(i) 54321

(ii) 8888

​(iii) 26005

​Ans:

(i) 

​(ii) 

​(iii) 

Q4: Express the number 87 in this base-5 symbolic system.

Ans: Start grouping with the largest landmark number smaller than 87, which is 5² = 25.
We get:

87 = 25 + 25 + 25 + 5 + 5 + 1 + 1

Using the standard symbols:

  • 5⁰ = 1 → ▲
  • 5¹ = 5 → ■
  • 5² = 25 → ⬡

So the number 87 in the new system is:

⬡ ⬡ ⬡ ■ ■ ▲ ▲

Q5: Add : XLVIII + XXXVI

Ans: Step 1: Write all symbols together:
X + L + V + I + I + I + X + X + X + V + I

Step 2: Group and simplify:

  • I + I + I + I = IV → but keep as V when grouped
  • V + V = X
  • X + X + X + X = XL

So the final result is LXXXIV.

Q6: Write Mesopotamian symbol representation for each number.

(i) 58

(ii) 214

(iii) 305

(iv) 499

(v) 7,281

Ans: 

(i) 58

​(ii) 214

​(iii) 305

Q7: Convert the decimal number 150 to its base-7 representation. Show your working and write the answer using digits from 0 to 6.

Ans:  To convert decimal 150 to base-7 :

Write the remainders in reverse order: 3 0 3

Q8: Express the number 999 in this new system.

Ans: Largest landmark number smaller than 999 is 5⁴ = 625.
We get:

999 = 625 + 125 + 125 + 125 + (–1) + … wait, no, careful:

Step-by-step:

999 – 625 = 374
Largest ≤ 374 is 125:
374 – 125 = 249

Another 125:
249 – 125 = 124
Largest ≤ 124 is 25:
124 – 25 = 99

Another 25:
99 – 25 = 74

Another 25:
74 – 25 = 49

Another 25:
49 – 25 = 24

Largest ≤ 24 is 5:
24 – 5 = 19

Another 5:
19 – 5 = 14

Another 5:
14 – 5 = 9

Another 5:
9 – 5 = 4

Largest ≤ 4 is 1:
4 – 1 = 3

Another 1:
3 – 1 = 2

Another 1:
2 – 1 = 1

Another 1:
1 – 1 = 0

So:
625 (5⁴) + 125 (5³) × 2 + 25 (5²) × 4 + 5 (5¹) × 4 + 1 (5⁰) × 4

Symbols:
~ ○ ○ ⬡ ⬡ ⬡ ⬡ ■ ■ ■ ■ ▲ ▲ ▲ ▲

Q9. Add the following numerals that are in the base-5 system that we created:

Remember that in this system, 5 times a landmark number gives the next one!

Ans: Let’s convert this to numerals

First numeral (left side)

This is: 1 circle, 2 hexagons, 1 square, 2 triangles

Value:

  • 1 × 125 = 125
  • 2 × 25 = 50
  • 1 × 5 = 5
  • 2 × 1 = 2

Sum: 125 + 50 + 5 + 2 = 182

Second numeral (right side):

Value:

  • 3 × 125 = 375
  • 1 × 25 = 25
  • 2 × 5 = 10
  • 2 × 1 = 2

Sum: 375 + 25 + 10 + 2 = 412

Q10: How would the Mesopotamians have written 20, 50, 100?

Ans: The Mesopotamian (Babylonian) system was a base-60 positional system using symbols for 1 (⟐) and 10 (⟐). Numbers were grouped into powers of 60, with a placeholder for zero in later periods. 
Assuming the simplified notation from Section 3.4:

  • 20: 20 = 20 × 1 = ⟐⟐ (two 10s).
  • 50: 50 = 5 × 10 = ⟐⟐⟐⟐⟐ (five 10s).
  • 100: 100 = 1 × 60 + 40 × 1 = ⟐,⟐⟐⟐⟐ (one 60 and four 10s).