Solve the Addition Problem: Calculate 15 + 7

Addition Strategies with Decomposition Methods

15+7= ? 15+7=\text{ ?}

❤️ 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

15+7= ? 15+7=\text{ ?}

2

Step-by-step solution

To solve 15+715 + 7, we can simplify the calculation by using a breakdown approach. Let's follow the steps:

  • First, recognize that 77 can be split into 5+25 + 2.
  • Next, calculate 15+515 + 5, which equals 2020.
  • Then, add the remaining 22 to the sum 2020.
  • This gives us a final answer of 2222.

The correct expression that represents this process is 15+5+215+5+2, which simplifies to 2222.

The given choices allow us to express the original problem differently. The choice that correctly represents our breakdown is:

15+5+215+5+2

3

Final Answer

15+5+2 15+5+2

Key Points to Remember

Essential concepts to master this topic
  • Rule: Break larger numbers into friendly parts for easier calculation
  • Technique: Split 7 into 5+2 because 15+5=20 is simple
  • Check: Verify that 15+5+2 equals 22 and matches 15+7 ✓

Common Mistakes

Avoid these frequent errors
  • Adding numbers incorrectly in decomposed form
    Don't just break apart numbers randomly without checking your arithmetic = wrong totals! Students often split correctly but then add 15+5+2 as 25 instead of 22. Always add each step carefully and verify your final sum matches the original problem.

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 break 7 into 5+2 instead of other combinations?

+

Breaking 7 into 5+2 makes the math easier because 15+5=20, which is a round number! Then 20+2=22 is simple. Other splits like 4+3 or 6+1 don't create such friendly calculations.

Do I always have to break numbers apart like this?

+

No! This is just one helpful strategy. You can add 15+7 directly if you're comfortable with it. Use whatever method feels easiest and most accurate for you.

How do I know which number to break apart?

+

Usually break apart the smaller number to create round numbers with the larger one. Here, breaking 7 lets us make 15+5=20, which is much easier than breaking 15.

What if I get a different answer using this method?

+

If your decomposed answer doesn't match the direct addition, check your arithmetic! Make sure 15+5+2 really equals 22, and that you split the original number correctly.

Can I use this strategy with bigger numbers?

+

Absolutely! This works great with larger numbers. For example, 47+8 becomes 47+3+5 = 50+5 = 55. Look for ways to make round numbers in your calculations.

🌟 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