Solve the Expression: Finding the Value of 21-4

Expression Equivalence with Multiple Subtraction

Which expression is equivalent to the given equation?

214= 21-4=

❤️ Continue Your Math Journey!

We have hundreds of course questions with personalized recommendations + Account 100% premium

Step-by-step written solution

Follow each step carefully to understand the complete solution
1

Understand the problem

Which expression is equivalent to the given equation?

214= 21-4=

2

Step-by-step solution

To solve this problem, we’ll follow these steps:

  • Step 1: Calculate the original expression 21421 - 4.
  • Step 2: Compare this result with each of the provided choices to find an equivalent expression.

Now, let's work through each step:
Step 1: The original expression 21421 - 4 simplifies directly to 1717.
Step 2: Check each choice:
- Choice 1: 2141=1621 - 4 - 1 = 16 (not equivalent)
- Choice 2: 2133=1521 - 3 - 3 = 15 (not equivalent)
- Choice 3: 2121=1821 - 2 - 1 = 18 (not equivalent)
- Choice 4: 2113=1721 - 1 - 3 = 17 (equivalent)

Therefore, the expression equivalent to 21421 - 4 is 2113 21 - 1 - 3 , which can also be written as 2113 21 - 1 - 3 .

3

Final Answer

2113 21-1-3

Key Points to Remember

Essential concepts to master this topic
  • Rule: Equivalent expressions must produce the same final result
  • Technique: Calculate each option: 2113=203=17 21-1-3 = 20-3 = 17
  • Check: Verify original equals chosen option: both 214 21-4 and 2113 21-1-3 equal 17 ✓

Common Mistakes

Avoid these frequent errors
  • Not calculating each option completely
    Don't assume expressions look equivalent without computing = wrong choices! Students often pick options that seem close without doing the math. Always calculate the original expression first, then compute each choice to find the match.

Practice Quiz

Test your knowledge with interactive questions

If we have 67 blocks in total, how many blocks will remain if we remove 5 tens and 4 ones?

FAQ

Everything you need to know about this question

Why can't I just look at the numbers and guess?

+

Math requires precision! Even if numbers look similar, small differences matter. 2141=16 21-4-1 = 16 but 214=17 21-4 = 17 - that extra subtraction changes everything!

Do I need to follow order of operations here?

+

Yes! Work from left to right for subtraction. 2113 21-1-3 means do 211=20 21-1 = 20 first, then 203=17 20-3 = 17 .

What if two expressions give the same answer?

+

That would mean both are correct! But in multiple choice questions, there's usually only one right answer. Double-check your calculations if you find duplicates.

Is there a shortcut to solve this faster?

+

Calculate the original first: 214=17 21-4 = 17 . Then quickly check each option until you find another expression that equals 17. Stop when you find the match!

Can I rearrange the subtraction order?

+

Be careful! Subtraction is not commutative. 2113 21-1-3 works left to right, but changing the order could give different results. Always follow the given expression exactly.

🌟 Unlock Your Math Potential

Get unlimited access to all 18 Natural Numbers around 100 questions, detailed video solutions, and personalized progress tracking.

📹

Unlimited Video Solutions

Step-by-step explanations for every problem

📊

Progress Analytics

Track your mastery across all topics

🚫

Ad-Free Learning

Focus on math without distractions

No credit card required • Cancel anytime

More Questions

Click on any question to see the complete solution with step-by-step explanations