Subtraction Within 20

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Answer Key & Explanations

Subtraction Within 20 · Grade 1 · Worksheet 2

1. 14 - 10 = ? Answer: 4 Solution: We are solving: 14 - 10 = ? We start with 14 and subtract 10 from it. Break it down if needed.
   Full step-by-step solution

   We are solving: 14 - 10 = ? Step 1: Understand the operation. We start with 14 and subtract 10 from it. Step 2: Break it down if needed. Think of 14 as 10 + 4. Subtracting 10 from 10 + 4 leaves 4. Step 3: Perform the subtraction directly. 14 - 10: Start from 14, count down 10: 14, 13 (1), 12 (2), 11 (3), 10 (4), 9 (5), 8 (6), 7 (7), 6 (8), 5 (9), 4 (10). We end at 4. Step 4: Verify. Addition is the inverse of subtraction: 4 + 10 = 14, which matches the original number. Step 5: Conclusion. 14 - 10 = 4.

2. 2 - 0 = ? Answer: 2 Solution: Start with the given problem: 2 - 0. Subtraction means taking away a certain quantity from another. Here, we are taking away 0 from 2.
   Full step-by-step solution

   Step 1: Start with the given problem: 2 - 0. Step 2: Understand the operation. Subtraction means taking away a certain quantity from another. Here, we are taking away 0 from 2. Step 3: Visualize the process. If you have 2 objects and you remove 0 objects, you still have all 2 objects. Step 4: Perform the calculation. Subtracting zero from any number does not change the number's value. Therefore, 2 minus 0 equals 2. Step 5: Write the final answer. The result of 2 - 0 is 2.

3. 14 - 14 = ? Answer: 0 Solution: Write down the problem. We have 14 minus 14. Understand what subtraction means.
   Full step-by-step solution

   Step 1: Write down the problem. We have 14 minus 14. Step 2: Understand what subtraction means. Subtraction finds the difference between two numbers. When we subtract a number from itself, we are asking how much is left. Step 3: Perform the calculation. Start with 14. Remove 14 from it. 14 - 14 = 0 Step 4: Explain the result. When you take away the entire quantity you started with, nothing remains. Therefore, the answer is 0. Final Answer: 0

4. 13 - 0 = ? Answer: 13 Solution: Identify the problem. We are subtracting 0 from 13. This can be written as: 13 - 0 Understand the meaning of subtracting zero.
   Full step-by-step solution

   Step 1: Identify the problem. We are subtracting 0 from 13. This can be written as: 13 - 0 Step 2: Understand the meaning of subtracting zero. Subtracting zero means taking away nothing from a number. If you start with 13 items and remove none, you still have 13 items. Step 3: Apply the subtraction rule for zero. For any number, subtracting zero leaves the number unchanged. So, 13 - 0 = 13 Step 4: Write the final answer. The result is 13.

5. 8 - 5 = ? Answer: 3 Solution: We start with the problem: 8 - 5 = ? Subtraction means taking away a certain number from another number. Here, we are taking away 5 from 8.
   Full step-by-step solution

   We start with the problem: 8 - 5 = ? Step 1: Understand the operation. Subtraction means taking away a certain number from another number. Here, we are taking away 5 from 8. Step 2: Count backwards if needed. Start from 8 and count down 5 steps: 8 → 7 (1 step), 7 → 6 (2 steps), 6 → 5 (3 steps), 5 → 4 (4 steps), 4 → 3 (5 steps). After 5 steps back, we land on 3. Step 3: Verify using addition. We know that subtraction is the inverse of addition. If 8 - 5 = ?, then ? + 5 should equal 8. 3 + 5 = 8, which is correct. Step 4: Conclusion. Therefore, 8 - 5 = 3.

6. 1 - 0 = ? Answer: 1 Solution: We start with the problem: 1 - 0. Subtraction means taking away a certain quantity from another. Here, we are taking away 0 from 1.
   Full step-by-step solution

   Step 1: We start with the problem: 1 - 0. Step 2: Subtraction means taking away a certain quantity from another. Here, we are taking away 0 from 1. Step 3: Taking away zero means we are removing nothing. The original amount, 1, remains unchanged. Step 4: Therefore, 1 minus 0 equals 1. Final Answer: 1

7. 13 - 3 = ? Answer: 10 Solution: We start with the problem: 13 − 3 = ? We are subtracting 3 from 13. This means we take away 3 items from 13 items.
   Full step-by-step solution

   We start with the problem: 13 − 3 = ? Step 1: Understand the operation. We are subtracting 3 from 13. This means we take away 3 items from 13 items. Step 2: Break it down if helpful. Think of 13 as 10 + 3. Subtracting 3 from 13: 13 − 3 = (10 + 3) − 3 = 10 + (3 − 3) = 10 + 0 = 10. Step 3: Verify by counting down. Start at 13, count back 3: 13 → 12 (1 less), 12 → 11 (2 less), 11 → 10 (3 less). We end at 10. Step 4: Conclusion. 13 − 3 = 10.

8. 7 - 1 = ? Answer: 6 Solution: We are solving: 7 - 1 = ? Start with the number 7. Subtracting 1 means we take away 1 from 7.
   Full step-by-step solution

   We are solving: 7 - 1 = ? Step 1: Start with the number 7. Step 2: Subtracting 1 means we take away 1 from 7. Step 3: Count back 1 from 7: 7 → 6. Step 4: So, 7 minus 1 equals 6. Final answer: 6

9. 6 - 1 = ? Answer: 5 Solution: We start with the problem: 6 - 1 = ? Identify the numbers involved. We have the number 6 and we are subtracting 1 from it.
   Full step-by-step solution

   We start with the problem: 6 - 1 = ? Step 1: Identify the numbers involved. We have the number 6 and we are subtracting 1 from it. Step 2: Understand what subtraction means. Subtraction means taking away a certain quantity from the original quantity. Here, we start with 6 objects and remove 1 object. Step 3: Perform the subtraction. If you have 6 items and take away 1 item, you are left with 5 items. So, 6 minus 1 equals 5. Step 4: Write the final answer. 6 - 1 = 5 The correct answer is 5.

10. 9 - 1 = ? Answer: 8 Solution: Start with the number 9. The problem asks us to subtract 1 from 9. Subtraction means we are taking away a quantity.
    Full step-by-step solution

    Step 1: Start with the number 9. Step 2: The problem asks us to subtract 1 from 9. Subtraction means we are taking away a quantity. Step 3: To visualize this, if you have 9 objects and you remove 1 object, you are left with 8 objects. Step 4: Write this as a mathematical operation: 9 minus 1 equals 8. Step 5: Therefore, the final answer is 8.