Addition is one of the most important foundational skills in mathematics. Once kids understand easy tricks, math becomes less stressful and more enjoyable. One such helpful concept is the addition of 9 with a two-digit number. Many kids find it tricky at first, but when taught using clear steps – as explained in learning videos then it becomes very simple and fun. This blog explains the method in an easy, step-by-step manner.
Understanding the Concept
Adding 9 to any number means increasing that number by nine. Instead of adding 9 directly, which can sometimes confuse kids, we use a smarter strategy:
Add 10 first and then subtract 1
This works because 9 is just 1 less than 10. This small adjustment makes addition faster and helps avoid mistakes.
Step-by-Step Method
Let us understand the steps with an example.
Example: 72 + 9
Step 1: Add 10 to the number
72 + 10 = 82
Adding 10 is easy because only the tens digit increases by 1.
Step 2: Subtract 1 from the result
82 − 1 = 81
Final Answer:
72 + 9 = 81
More Examples
Example 1: 56 + 9
Step 1: 56 + 10 = 66
Step 2: 66 − 1 = 65
Answer: 65
Example 2: 44 + 9
Step 1: 44 + 10 = 54
Step 2: 54 − 1 = 53
Answer: 53
Example 3: 89 + 9
Step 1: 89 + 10 = 99
Step 2: 99 − 1 = 98
Answer: 98
Why This Method Works Well
This method is widely used in teaching videos because:
- Adding 10 is simple and quick
- It improves mental math skills
- It reduces confusion and counting errors
- It builds confidence in young learners
Students can solve problems faster and more accurately using this strategy.
Recommended reading: Addition in Geometry
Common Mistakes to Avoid
- Forgetting to subtract 1 after adding 10
- Writing the intermediate result as the final answer
- Skipping steps too quickly
Careful practice helps overcome these errors.
Learning Tips
- Speak each step aloud while solving
- Practice daily with different numbers
- Use number charts or visual aids
- Watch step-by-step videos repeatedly
Recommended reading: Basic Addition
Curious about the ‘how’ and ‘why’? Watch the full explanation here:
Conclusion
Adding 9 to a two-digit number becomes easy when students follow the simple steps shown in learning videos: add 10 and subtract 1. This method saves time, reduces errors, and strengthens number understanding. With regular practice, kids can master this technique and apply it confidently in exams and daily life.
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FAQs
Q1. Why do we add 10 and subtract 1 instead of adding 9 directly?
Adding 10 is easier and faster than adding 9. Since 9 is just 1 less than 10, subtracting 1 after adding 10 gives the correct answer with less effort.
Q2. Is this method useful for all two-digit numbers?
Yes, this method works for all two-digit numbers and is especially helpful for mental math and quick calculations.
