The Decimal Structure up to 10,000: Place value of digits

Examples with solutions for The Decimal Structure up to 10,000: Place value of digits

Exercise #1

Choose a number greater than 1029 whose thousandth digit is 4 less than its units digit.

Step-by-Step Solution

To solve this problem, we will evaluate each choice to find the number where the thousandth digit is 4 less than its units digit, and the entire number is greater than 1029.

  • Choice 1: 1037 1037

  • Thousandth digit is 1, unit digit is 7. The difference is 71=6 7 - 1 = 6 , which does not satisfy the condition (needs to be 4).

  • Choice 2: 408 408

  • This does not meet the requirement of being greater than 1029.

  • Choice 3: 1025 1025

  • Thousandth digit is 1, unit digit is 5. The difference is 51=4 5 - 1 = 4 , which meets the condition. However, 1025 1025 is not greater than 1029 1029 .

  • Choice 4: 1235 1235

  • Thousandth digit is 1, unit digit is 5. The difference is 51=4 5 - 1 = 4 , and the number is greater than 1029 1029 . This satisfies all conditions.

Therefore, among the given options, the correctly chosen number is 1235 1235 .

Answer

1235 1235

Exercise #2

Which number has the same thousands digit and tens digit?

Step-by-Step Solution

To solve the problem, we will examine each number given and evaluate the digits in the thousands and tens places:

  • 5105 5105 : The thousands digit is 5 5 and the tens digit is 0 0 . They are not the same.
  • 4140 4140 : The thousands digit is 4 4 and the tens digit is also 4 4 . They are the same.
  • 2333 2333 : The thousands digit is 2 2 and the tens digit is 3 3 . They are not the same.
  • 1121 1121 : The thousands digit is 1 1 and the tens digit is 2 2 . They are not the same.

Based on the analysis above, the only number in which the thousands digit is the same as the tens digit is 4140 4140 .

Therefore, the solution to the problem is 4140 4140 .

Answer

4140 4140

Exercise #3

Which number has a thousands digit of 4 and a hundreds digit that is smaller than its thousands digit?

Step-by-Step Solution

To solve this problem, let's start by considering the criteria:

  • The thousands digit of the number must be 4, which represents values in the format 4XXX 4XXX .
  • The hundreds digit must be less than 4, meaning it can be 0, 1, 2, or 3.

Given these constraints, let's consider the provided choices:

  1. 4321 4321 :
    - Thousands digit is 4.
    - Hundreds digit is 3 (which is less than 4).
    - This choice satisfies both conditions.
  2. 3321 3321 :
    - Thousands digit is 3.
    - This does not satisfy the condition of having a thousands digit of 4. Therefore, it's incorrect.
  3. 1200 1200 :
    - Thousands digit is 1.
    - This does not satisfy the condition of having a thousands digit of 4. Therefore, it's incorrect.
  4. 4789 4789 :
    - Thousands digit is 4.
    - Hundreds digit is 7 (which is not less than 4).
    - This choice does not satisfy the condition of having a hundreds digit less than the thousands digit. Therefore, it's incorrect.

Therefore, the number that meets all the conditions is 4321 4321 .

Answer

4321 4321

Exercise #4

Choose a number whose unit digit is three times greater than its tens digit.

Step-by-Step Solution

To solve this problem, choose a number from the options where the unit digit is three times the tens digit:

  • Option 1: 8642 8642
    Tens digit: 4 4 , Units digit: 2 2 .
    Units is not three times tens. Reject.
  • Option 2: 5846 5846
    Tens digit: 4 4 , Units digit: 6 6 .
    Units is not three times tens. Reject.
  • Option 3: 3257 3257
    Tens digit: 5 5 , Units digit: 7 7 .
    Units is not three times tens. Reject.
  • Option 4: 1426 1426
    Tens digit: 2 2 , Units digit: 6 6 .
    Six is three times two. Accept.

Thus, the correct number in question is 1426 1426 .

Answer

1426 1426

Exercise #5

Choose a 4-digit number whose tens digit is equal to its thousands digit and is less than 2200.

Step-by-Step Solution

To solve this problem, we should carefully examine each of the provided choices, ensuring they meet all necessary criteria:

  • The number should be a 4-digit number.
  • The tens digit should be equal to the thousands digit.
  • The number should be less than 2200.

Let's analyze each option:

1. 2220 2220 :
Thousands digit = 2, Tens digit = 2 (Condition satisfied that they are equal)
However, the number is greater than 2200.

2. 2002 2002 :
Thousands digit = 2, Tens digit = 0 (Condition not satisfied as digits are different)
The number itself is less than 2200.

3. 2020 2020 :
Thousands digit = 2, Tens digit = 2 (Condition satisfied that they are equal)
The number is less than 2200.

4. 2222 2222 :
Thousands digit = 2, Tens digit = 2 (Condition satisfied that they are equal)
The number is greater than 2200.

From this breakdown, the number that satisfies both necessary conditions is 2020 2020 .

Thus, the correct answer is 2020 2020 .

Answer

2020 2020