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Solve multi-digit subtraction problems

Estimate differences
Use various subtraction ?
Solve real world problems

1 answer

Sure! Let's go through some multi-digit subtraction problems, estimates, and real-world application problems.

Multi-Digit Subtraction Problems

  1. Problem: \( 582 - 247 \)

    Solution:

         582
   - 247
   ------
     335

    So, \( 582 - 247 = 335 \).

  2. Problem: \( 9453 - 6789 \)

    Solution:

          9453
    - 6789
    ------
      2664

    Thus, \( 9453 - 6789 = 2664 \).

Estimating Differences

To estimate a subtraction, we round the numbers to the nearest ten or hundred.

  1. Problem: Estimate \( 572 - 289 \)

    Estimation: \( 570 - 290 = 280 \) (rounded to nearest tens)

  2. Problem: Estimate \( 4632 - 2789 \)

    Estimation: \( 4600 - 2800 = 1800 \) (rounded to nearest hundreds)

Various Subtraction Strategies

  1. Standard Algorithm: This is what we used above for multi-digit subtraction.

  2. Counting Up: Instead of subtracting, count how many you need to add to get from the smaller number to the larger one.

  3. Breaking Numbers Apart: Break the numbers down into smaller, manageable parts.

    Example: \( 839 - 274 \)

    • Break it down:
    • \( 839 - 200 = 639\)
    • \( 639 - 70 = 569\)
    • \( 569 - 4 = 565\)

Thus, \( 839 - 274 = 565 \).

Solving Real-World Problems

  1. Problem: A bookstore had 1,200 books. After a sale, 458 books were sold. How many books are left?

    Solution:

    • \( 1200 - 458 = 742 \)
    • Therefore, there are 742 books left.

  2. Problem: A car traveled 375 miles in the first part of the journey and then traveled 189 miles in the second part. How many miles did the car travel in total?

    Note: This is an addition problem, but we can think about it in terms of subtraction from a certain total. If the total distance it could travel is 700 miles, we could look at how much is left after both legs.

    • Total: \( 700 - (375 + 189) = 700 - 564 = 136 \)
    • The car can still travel 136 miles.

  3. Problem: Maria has $500 in her bank account. She spends $189 on groceries and $275 on bills. How much money does she have left?

    Solution:

    • First, find the total amount spent: \[ 189 + 275 = 464 \]
    • Then subtract from the total money: \[ 500 - 464 = 36 \]
    • Thus, Maria has $36 left.

Feel free to ask for any specific problems or areas you'd like to explore further!