Real-World Examples of Unknowns in Grade 4 Subtraction

📚 Quick Study Guide

• 🔢 Understanding Unknowns: An unknown in subtraction is a missing number represented by a symbol (like a box or a letter) that we need to find.
• ➖ Subtraction Formula: The basic subtraction formula is: $a - b = c$, where 'a' is the number being subtracted from, 'b' is the number being subtracted, and 'c' is the difference.
• 💡 Finding the Unknown: To find the unknown, think about what number needs to be added or subtracted to make the equation true. For example, if $10 - [] = 6$, then $10 - 6 = 4$, so the unknown is 4.
• 🧮 Using Inverse Operations: Use addition to check your subtraction and vice-versa. If you have $x - 3 = 7$, then $x = 7 + 3 = 10$.
• ✍️ Real-World Application: Think of practical problems like sharing cookies, giving away toys, or calculating change to better understand subtraction with unknowns.

🧪 Practice Quiz

1. What number goes in the box to make this equation true? $15 - [] = 9$
   1. 6
   2. 7
   3. 8
   4. 9
2. Maria had 20 stickers. She gave some to her friend. Now she has 12 stickers. How many stickers did she give away? $20 - [] = 12$
   1. 6
   2. 7
   3. 8
   4. 9
3. John had some candies. He ate 5 candies, and now he has 8 candies left. How many candies did John have at first? $[] - 5 = 8$
   1. 11
   2. 12
   3. 13
   4. 14
4. Solve for the unknown: [] - 7 = 3
   1. 8
   2. 9
   3. 10
   4. 11
5. A baker baked 24 cookies. After selling some, he had 11 cookies left. How many cookies did he sell? $24 - [] = 11$
   1. 12
   2. 13
   3. 14
   4. 15
6. What number makes the equation true? 18 - [] = 5
   1. 11
   2. 12
   3. 13
   4. 14
7. There were [] birds on a tree. 6 flew away, and now there are 7 birds. How many birds were on the tree at first? $[] - 6 = 7$
   1. 11
   2. 12
   3. 13
   4. 14