Objective practice questions on the number system for students, focusing on digit formation, numerical comparisons, and unit conversions.

Let's solve each question step by step:

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Question 1: Smallest five-digit number that can be formed using 3, 2, 7, 0, 8 is ______.

#### Solution:
To form the smallest five-digit number using the digits 3, 2, 7, 0, 8:
1. The smallest digit should be placed in the highest place value (leftmost position). However, a five-digit number cannot start with 0.
2. The next smallest digit is 2, so we place 2 in the leftmost position.
3. Arrange the remaining digits (0, 3, 7, 8) in ascending order to get the smallest number.

Thus, the smallest five-digit number is: 20378.

#### Correct Answer:
D. 20378

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Question 2: One million is equal to ______.

#### Solution:
- One million is written as 1,000,000.
- In the Indian numbering system:
- 1 lakh = 100,000
- 1 crore = 10,000,000
- To convert one million into the Indian system:
- \( 1,000,000 \div 1,00,000 = 10 \)
- Therefore, one million is equal to 10 lakhs.

#### Correct Answer:
C. 10 lakhs

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Question 3: Largest 6-digit number is ______.

#### Solution:
The largest 6-digit number is formed by placing the digit 9 in all six places:
- The largest 6-digit number is 999,999.

#### Correct Answer:
B. 999999

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Question 4: Smallest 8-digit number is equal to ______.

#### Solution:
The smallest 8-digit number is formed by placing the digit 1 in the leftmost position and 0 in all other positions:
- The smallest 8-digit number is 10,000,000.
- In the Indian numbering system:
- 1 crore = 10,000,000

#### Correct Answer:
C. 1 crore

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Question 5: One less than 2,97,73000 is ______.

#### Solution:
To find one less than 2,97,73000:
1. Subtract 1 from 2,97,73000:
\[
2,97,73000 - 1 = 2,97,72999
\]

#### Correct Answer:
C. 2,97,72999

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Final Answers:

1. D. 20378
2. C. 10 lakhs
3. B. 999999
4. C. 1 crore
5. C. 2,97,72999

\boxed{D, C, B, C, C}