Number System Worksheet-3: Fill-in-the-blanks exercise for students to practice Roman numerals, number properties, and basic math concepts.

Let’s go through each question one by one and solve them carefully.

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(1) In Roman system, smaller symbol written to the left of the larger symbol is always subtracted from the larger symbols.
→ Example: IV = 5 - 1 = 4

(2) In Roman system, smaller symbol written to the right of the larger symbol is always added to the larger symbol.
→ Example: VI = 5 + 1 = 6

(3) Repetition of a symbol in roman system means addition.
→ Example: III = 1 + 1 + 1 = 3

(4) If I have 10 crore rupees then, the International officer will say, “I have 100 million rupees”.
→ Because 1 crore = 10 million → 10 crore = 10 × 10 million = 100 million

(5) C can be subtracted from D and M only.
→ Rules: C (100) can be placed before D (500) or M (1000) to make CD (400) or CM (900)

(6) XIV + IV + CD + V is _______
Break it down:
- XIV = 10 + 4 = 14
- IV = 4
- CD = 400
- V = 5
Add: 14 + 4 = 18; 18 + 400 = 418; 418 + 5 = 423

(7) TV costing 12199 + DVD player worth 4090 Approximate cost?
We round both numbers:
- 12199 ≈ 12000
- 4090 ≈ 4000
Total ≈ 12000 + 4000 = 16000

*(Note: Some might round 12199 to 12200 and 4090 to 4100 → 16300, but since it says “approximate” and doesn’t specify rounding rule, 16000 is acceptable for estimation at this level.)*

But let’s check exact sum first:
12199 + 4090 = 16289 → which rounds to 16000 if rounding to nearest thousand.

So answer: 16000

(8) To make one Gulab-jamun, need 10 gm ingredients. From 5 Kg ingredients, how many gulab-jamuns?
First, convert kg to gm: 5 Kg = 5000 gm
Each needs 10 gm → Number = 5000 ÷ 10 = 500

(9) ___ lakhs make 1 million
1 million = 10,00,000
1 lakh = 1,00,000
So, 10,00,000 ÷ 1,00,000 = 10

(10) If a number is divisible by 2 then it is called even number.

(11) If a number is not divisible by 2 then it is called odd number.

(12) Math teacher has even chalk sticks, English teacher has odd. Total = even + odd = odd
Because: even + odd = always odd
Example: 2 + 3 = 5 (odd)

(13) 1 is neither prime nor composite natural number.
(Prime numbers have exactly two factors: 1 and itself. Composite have more than two. 1 has only one factor.)

(14) 802 is divisible by ________.
Check divisibility rules:
- By 2? Last digit is 2 → yes → 802 ÷ 2 = 401
- Is 401 prime? Let’s see — not divisible by 2,3,5,7,11,13,17,19 → so 802 = 2 × 401
So divisors are 1, 2, 401, 802
Question says “divisible by ________” — probably expects smallest non-trivial divisor → 2

But sometimes they want all — but blank suggests one answer. Since it's even, 2 is safe.

Alternatively, maybe they expect “2 and 401”, but blank is singular. So best answer: 2

Wait — actually, looking again: “802 is divisible by __________.” — could be multiple, but format implies one. Most basic answer: 2

(15) 2 is the only even prime number.

(16) Greatest two-digit prime number?
Two-digit primes: 97, 89, 83...
97 is prime → check: not divisible by 2,3,5,7 → 7×13=91, 7×14=98 → so 97 is prime.
Answer: 97

(17) The order, in which we arrange the numbers from smallest to largest → Ascending order

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Now compiling final answers:

Final Answer:
(1) left
(2) added
(3) addition
(4) 100 million
(5) D, M
(6) 423
(7) 16000
(8) 500
(9) 10
(10) even
(11) odd
(12) odd
(13) 1
(14) 2
(15) 2
(16) 97
(17) Ascending order