Olympiad Test: Whole Numbers - Class 6 MCQ

• Whole numbers start from 0 and go on as 0, 1, 2, 3, …
• A predecessor means the number just before another in this sequence.
• 0 is the very first whole number.
• Since there’s no number before 0, it has no predecessor.
• Every other option (1, 2, etc.) has a preceding number.
• Hence, 0 is the whole number without a predecessor.

The smallest four-digit number is 1000. Therefore, its predecessor is:

• 1000 - 1 = 999

1 million is written as 1,000,000. Its predecessor is 1,000,000 − 1 = 999,999.

The smallest whole number is 0, and the greatest 2-digit number is 99. Whole numbers between them are from 1 to 98.
Count: 99 - 0 - 1 = 98.

• Start with 99−0:
  Subtract the smallest whole number (0) from the greatest 2-digit number (99), which gives 99.
  This step counts all whole numbers from 0 to 99, inclusive.

• Subtract 1:
  To exclude both the smallest whole number (0) and the greatest 2-digit number (99) from the total count, we subtract 1 for 0 and another 1 for 99. Hence, we subtract 1.

Only when a = 0 does the equation a + a = a hold true because:

• 0 + 0 = 0

Using the distributive property, we factor out 93 from both terms:

• 93 × (63 + 37)
• = 93 × 100
• = 9300.

For option A, the calculation is:

• (5 − 0) ÷ 5 = 1, which is not zero.

Options B, C, and D all result in:

• 0

Therefore, the correct answer is A.

Whole numbers are non-negative integers (e.g., 0, 1, 2, ...).

• For option A: 13 - 21 = -8, which is not a whole number. Therefore, statement A is true.
• Option B: 21 × 1 = 21 and 21 × 0 = 0. Since 21 ≠ 0, statement B is false.
• Option C: 21 - 13 = 8, which is a whole number. Therefore, statement C is false.
• Option D:
  • Left side: 21 - (13 - 5) = 21 - 8 = 13;
  • Right side: (21 - 13) - 5 = 8 - 5 = 3.
  Since 13 ≠ 3, statement D is false.

Thus, the correct answer is A.

Whole numbers between 38 and 68 range from 39 to 67. Count: 67 − 39 + 1 = 29.

The smallest 6-digit number is 100000. Adding 5 to this number results in:

• 100000 + 5 = 100005

Therefore, the correct answer is D.

The smallest 5-digit number is 10000. Subtracting 578 gives 10000 − 578 = 9422.

The successor of a number is obtained by adding 1 to it. Therefore:

• 100199 + 1 equals 100200.

In the whole number system, which includes all non-negative integers starting from 0:

• 0 is the first number.
• It does not have a predecessor.
• There are no negative numbers or fractions in this system.

Therefore, 0 has no number that comes before it.

Whole numbers include all non-negative integers starting from 0. They are defined as:

• 0
• 1
• 2
• 3
• 4
• 5
• and so on.

This makes 0 the smallest whole number.

The smallest 2-digit number is 10. Its predecessor is 9, and successor is 11. The product is 9×11=99.