Subtract 30 Units from 85: Place Value Practice Problem

Two-Digit Subtraction with Place Value Understanding

What number do you get if you subtract thirty units from the number 85?

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Step-by-step written solution

Follow each step carefully to understand the complete solution
1

Understand the problem

What number do you get if you subtract thirty units from the number 85?

2

Step-by-step solution

To solve this problem, we'll perform basic subtraction.

  • Step 1: Identify the minuend and subtrahend.

  • The minuend (the number from which we are subtracting) is 85.

  • The subtrahend (the number to be subtracted) is 30.

  • Step 2: Apply the subtraction formula 8530 85 - 30 .

  • Step 3: Calculate the difference.

  • Subtract 30 from 85 as follows:
    8530=55 85 - 30 = 55

Therefore, the solution to the problem is 55 55 .

3

Final Answer

55 55

Key Points to Remember

Essential concepts to master this topic
  • Place Value Rule: Units subtract from units, tens from tens
  • Technique: Break down 85 - 30 as (80 + 5) - 30 = 50 + 5
  • Check: Add answer back: 55 + 30 = 85 ✓

Common Mistakes

Avoid these frequent errors
  • Subtracting in wrong order or place value positions
    Don't subtract 85 - 03 = 82 by mixing up place values! This reverses the subtrahend digits and gives the wrong result. Always align numbers by place value: 85 - 30 means 8 tens minus 3 tens, 5 ones minus 0 ones.

Practice Quiz

Test your knowledge with interactive questions

If we have 85 blocks in total, how many blocks will remain if we remove 4 tens and 1 one?

FAQ

Everything you need to know about this question

What does 'thirty units' mean exactly?

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Thirty units means the same as the number 30. In math, units is another word for ones, so thirty units = 3 tens + 0 ones = 30.

Why is the answer 55 and not 65?

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When we subtract 30 from 85, we take away 3 tens from the 8 tens, leaving us with 5 tens = 50. The 5 ones stay the same, so 50 + 5 = 55.

How do I know I subtracted correctly?

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Use addition to check! Add your answer to what you subtracted: 55 + 30. If you get back to your original number (85), you're correct!

Can I use the blocks diagram to help solve this?

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Yes! The diagram shows base-10 blocks. Count the blocks representing 85, then remove 30 blocks (3 tens). Count what remains to verify your answer.

What if I get confused about which number to subtract from which?

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Remember: subtract FROM means the first number is bigger. 'Subtract 30 from 85' means 85 - 30, not 30 - 85!

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