Solved problems: Adding 2-digit numbers with friendly numbers (regrouping examples)

📚 Quick Study Guide

• 🔢 Friendly numbers are numbers that end in zero (like 10, 20, 30, etc.) or are easy to work with (like 5, 25, 50, etc.).
• ➕ When adding 2-digit numbers, you can break down one of the numbers to make the other number a friendly number.
• 🧮 Example: To add $28 + 15$, you can break down 15 into $2 + 13$. Then, add $2$ to $28$ to make $30$. Finally, add $30 + 13 = 43$.
• 💡 Regrouping involves moving values from one place value to another to simplify addition.
• 📝 Always double-check your work to ensure accuracy!

Practice Quiz

1. What is the first step in adding $36 + 17$ using friendly numbers?
   1. Add the ones digits directly.
   2. Break down 17 into friendly numbers.
   3. Add the tens digits directly.
   4. Regroup the tens and ones.
2. How can you make $48$ a friendly number when adding $48 + 23$?
   1. Add 3 to make it 50.
   2. Subtract 3 to make it 45.
   3. Add 2 to make it 50.
   4. Subtract 2 to make it 46.
3. What is $25 + 15$ using friendly numbers?
   1. 30
   2. 35
   3. 40
   4. 45
4. Solve: $52 + 19 = $?
   1. 61
   2. 71
   3. 70
   4. 69
5. What is the sum of $67 + 24$ using the friendly number strategy?
   1. 81
   2. 91
   3. 90
   4. 80
6. Calculate: $34 + 27 = $?
   1. 51
   2. 60
   3. 61
   4. 59
7. Find the total: $45 + 36 = $?
   1. 71
   2. 81
   3. 80
   4. 79