Decompose Numbers to 10

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Answer Key & Explanations

Decompose Numbers to 10 · Kindergarten · Worksheet 3

1. 10 = 7 + ? Answer: 3 Solution: We know that 10 = 7 + ? Think about what number added to 7 equals 10 7 + 3 = 10 So the missing number is 3 The answer is 3.
   Full step-by-step solution

   Step 1: We know that 10 = 7 + ? Step 2: Think about what number added to 7 equals 10 Step 3: 7 + 3 = 10 Step 4: So the missing number is 3 The answer is 3.

2. 4 = ? + 2 Answer: 2 Solution: Since 2 + 2 = 4, we know that 4 = 2 + 2.
3. Tane sees 9 triangles drawn in a row: ▲ ▲ ▲ ▲ ▲ ▲ ▲ ▲ ▲. He circles 4 of them. How many triangles are not circled? Answer: 5 Solution: Start with 9 triangles. Step 2: 4 triangles are circled. Step 3: Subtract the circled triangles from the total: 9 - 4 = 5.
   Full step-by-step solution

   Step 1: Start with 9 triangles. Step 2: 4 triangles are circled. Step 3: Subtract the circled triangles from the total: 9 - 4 = 5. Step 4: There are 5 triangles not circled. The answer is 5.

4. 7 = 3 + ? Answer: 4 Solution: We know that 7 = 3 + ? Start with 3 and count up to 7: 3, 4, 5, 6, 7 Count how many numbers we added: 4, 5, 6, 7 (that's 4 numbers) So 3 + 4 = 7 The answer is 4.
   Full step-by-step solution

   Step 1: We know that 7 = 3 + ? Step 2: Start with 3 and count up to 7: 3, 4, 5, 6, 7 Step 3: Count how many numbers we added: 4, 5, 6, 7 (that's 4 numbers) Step 4: So 3 + 4 = 7 The answer is 4.

5. Lily has 8 colorful blocks. She puts 3 blocks in a red box and the rest in a blue box. How many blocks are in the blue box? Answer: 5 Solution: Lily has 8 blocks in total. She puts 3 blocks in the red box. The rest go into the blue box.
   Full step-by-step solution

   Step 1: Understand the problem. Lily has 8 blocks in total. She puts 3 blocks in the red box. The rest go into the blue box. We need to find how many blocks are in the blue box. Step 2: Identify the total number of blocks. Total blocks = 8. Step 3: Identify how many blocks are in the red box. Red box = 3 blocks. Step 4: Find the number of blocks in the blue box. Since the rest of the blocks go into the blue box, we subtract the red box blocks from the total blocks: Blue box blocks = Total blocks - Red box blocks Blue box blocks = 8 - 3 Step 5: Perform the calculation. 8 - 3 = 5 Step 6: State the final answer. The blue box has 5 blocks.

6. Jordan sees 7 birds on a fence. 5 of them fly away. How many birds are still on the fence? Answer: 2 Solution: Start with 7 birds on the fence. 5 birds fly away, so we subtract: 7 - 5 = 2.
   Full step-by-step solution

   Step 1: Start with 7 birds on the fence. Step 2: 5 birds fly away, so we subtract: 7 - 5 = 2. The answer is 2.

7. 9 = ? + 9 Answer: 0 Solution: Since 0 + 9 = 9, we know that 9 = 0 + 9.
8. There are 8 circles arranged in a pattern: ○ ○ ○ ○ | ○ ○ ○ ○. How many circles are in each group? Answer: 4 Solution: 1. First, look at the pattern: There are 8 circles in total, separated into two groups by the vertical line. 2.
   Full step-by-step solution

   Let's go step-by-step. 1. First, look at the pattern: ○ ○ ○ ○ | ○ ○ ○ ○ There are 8 circles in total, separated into two groups by the vertical line. 2. The problem asks: "How many circles are in each group?" This means we need to count how many circles are on the left side of the line and how many on the right side. 3. Count the circles on the left of the line: ○ ○ ○ ○ → that's 4 circles. 4. Count the circles on the right of the line: ○ ○ ○ ○ → that's 4 circles. 5. Since both groups have the same number, the answer is 4. Final answer: 4

9. 9 = ? + 8 Answer: 1 Solution: Since 1 + 8 = 9, we know that 9 = 1 + 8.
10. Lily has 8 crayons. 2 are red and the rest are blue. How many blue crayons does Lily have? Answer: 6 Solution: Lily has 8 crayons total. 2 are red, so we find the blue ones by subtracting: 8 - 2 = 6.
    Full step-by-step solution

    Step 1: Lily has 8 crayons total. Step 2: 2 are red, so we find the blue ones by subtracting: 8 - 2 = 6. The answer is 6.