Subtraction Within 100

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Answer Key & Explanations

Subtraction Within 100 · Grade 2 · Worksheet 1

1. 83 - 46 = ? Answer: 37 Solution: 83 -46 Look at the ones place: 3 - 6. Since 3 is smaller than 6, we need to regroup. Take 1 ten from the 8 tens, leaving 7 tens.
   Full step-by-step solution

   Step 1: Write the problem vertically: 83 -46 --- Step 2: Look at the ones place: 3 - 6. Since 3 is smaller than 6, we need to regroup. Step 3: Take 1 ten from the 8 tens, leaving 7 tens. Add 10 ones to the 3 ones, making 13 ones. Step 4: Now subtract in the ones place: 13 - 6 = 7 Step 5: Subtract in the tens place: 7 - 4 = 3 Step 6: Combine the results: 3 tens and 7 ones = 37 The answer is 37.

2. 73 - 28 = ? Answer: 45 Solution: 73 - 28 Start with the ones column (rightmost digits): 3 - 8. Since 3 is smaller than 8, we cannot subtract directly. We need to borrow from the tens column.
   Full step-by-step solution

   Let's solve 73 - 28 step-by-step. Step 1: Write the problem vertically in your mind: 73 - 28 Step 2: Start with the ones column (rightmost digits): 3 - 8. Since 3 is smaller than 8, we cannot subtract directly. We need to borrow from the tens column. Step 3: Borrow 1 from the 7 in the tens column. The 7 becomes 6, and the 3 in the ones column becomes 13 (because 1 ten = 10 ones, so 10 + 3 = 13). Step 4: Now subtract in the ones column: 13 - 8 = 5. Write down 5 in the ones place of the answer. Step 5: Move to the tens column: We now have 6 (after borrowing) - 2 = 4. Write down 4 in the tens place of the answer. Step 6: Combine the digits: The tens digit is 4 and the ones digit is 5, so the answer is 45. Final check: 73 - 28 = 45 is correct because 45 + 28 = 73. ANSWER: 45

3. Liam had 72 stickers in his collection. He gave 28 stickers to his friend Noah for his birthday. How many stickers does Liam have left? Answer: 44 Solution: Liam started with 72 stickers. He gave away 28 stickers to Noah. To find how many he has left, subtract the stickers he gave away from the stickers he started with.
   Full step-by-step solution

   Liam started with 72 stickers. He gave away 28 stickers to Noah. To find how many he has left, subtract the stickers he gave away from the stickers he started with. Step 1: Write the subtraction problem: 72 - 28 Step 2: Subtract the ones place first: 2 - 8 cannot be done without regrouping. So, take one ten from the 7 tens (which is 10 ones) and add it to the 2 ones. That makes 7 tens become 6 tens, and 2 ones become 12 ones. Step 3: Now subtract the ones: 12 - 8 = 4 Step 4: Subtract the tens: 6 - 2 = 4 Step 5: Combine the results: 4 tens and 4 ones = 44 So, Liam has 44 stickers left.

4. Emma had 92 stickers in her sticker book. She used 45 stickers to decorate her art project. How many stickers does Emma have left in her sticker book? Answer: 47 Solution: Start with 92 stickers Subtract 45 stickers that were used Since we can't subtract 5 from 2 in the ones place, we need to regroup Take 1 ten from the 9 tens, leaving 8 tens Add that 1 ten (which is 10 ones) to the 2 ones, making 12 ones Now subtract: 12 ones minus 5 ones equals 7 ones 8 tens…
   Full step-by-step solution

   Step 1: Start with 92 stickers Step 2: Subtract 45 stickers that were used Step 3: Since we can't subtract 5 from 2 in the ones place, we need to regroup Step 4: Take 1 ten from the 9 tens, leaving 8 tens Step 5: Add that 1 ten (which is 10 ones) to the 2 ones, making 12 ones Step 6: Now subtract: 12 ones minus 5 ones equals 7 ones Step 7: 8 tens minus 4 tens equals 4 tens Step 8: Combine the results: 4 tens and 7 ones equals 47 Emma has 47 stickers left.

5. Noah has 93 building blocks. He uses 47 blocks to build a tower. How many blocks does Noah have left? Answer: 46 Solution: Start with 93 blocks. Subtract 47 blocks. Subtract the ones: 3 - 7.
   Full step-by-step solution

   Step 1: Start with 93 blocks. Step 2: Subtract 47 blocks. Step 3: Subtract the ones: 3 - 7. Since 3 is less than 7, borrow 1 ten from the tens place. 93 becomes 80 + 13. Now subtract the ones: 13 - 7 = 6. Step 4: Subtract the tens: 8 - 4 = 4. Step 5: Combine the tens and ones: 40 + 6 = 46. The answer is 46.

6. 64 - 29 = ? Answer: 35 Solution: 64 - 29 Look at the ones place: 4 - 9. Since 4 is smaller than 9, we need to regroup. Take 1 ten from the 6 tens, leaving 5 tens.
   Full step-by-step solution

   Step 1: Write the problem vertically: 64 - 29 ----- Step 2: Look at the ones place: 4 - 9. Since 4 is smaller than 9, we need to regroup. Step 3: Take 1 ten from the 6 tens, leaving 5 tens. Add that 1 ten (which is 10 ones) to the 4 ones, giving us 14 ones. Step 4: Now subtract the ones: 14 - 9 = 5 Step 5: Subtract the tens: 5 - 2 = 3 Step 6: Combine the results: 3 tens and 5 ones = 35 The answer is 35.

7. Tane picked 67 flowers from the garden. Then Tane gave 50 flowers to mom. How many flowers does Tane have left? Answer: 17 Solution: Tane picked 67 flowers. Tane gave away 50 flowers, so subtract: 67 - 50 = 17. Tane has 17 flowers left.
   Full step-by-step solution

   Step 1: Tane picked 67 flowers. Step 2: Tane gave away 50 flowers, so subtract: 67 - 50 = 17. Tane has 17 flowers left.

8. 76 - 49 = ? Answer: 27 Solution: 76 -49 Look at the ones place: 6 - 9. Since 6 is smaller than 9, we need to regroup. Take 1 ten from the 7 tens, leaving 6 tens.
   Full step-by-step solution

   Step 1: Write the problem vertically: 76 -49 --- Step 2: Look at the ones place: 6 - 9. Since 6 is smaller than 9, we need to regroup. Step 3: Take 1 ten from the 7 tens, leaving 6 tens. Add 10 ones to the 6 ones, making 16 ones. Step 4: Now subtract in the ones place: 16 - 9 = 7 Step 5: Subtract in the tens place: 6 - 4 = 2 Step 6: Combine the results: 2 tens and 7 ones = 27 The answer is 27.

9. Lily had 75 stickers in her collection. She gave 28 stickers to her friend Emma. How many stickers does Lily have left? Answer: 47 Solution: Lily starts with 75 stickers. She gives 28 stickers to Emma. This means we subtract 28 from 75.
   Full step-by-step solution

   Let's solve this step by step. Step 1: Lily starts with 75 stickers. Step 2: She gives 28 stickers to Emma. This means we subtract 28 from 75. Step 3: Write the subtraction: 75 - 28 Step 4: Subtract the ones place first: 5 - 8 is not possible without regrouping. So, we take 1 ten from the 7 tens (which is 10 ones) and add it to the 5 ones. That makes 7 tens become 6 tens, and 5 ones become 15 ones. Step 5: Now subtract the ones: 15 - 8 = 7 Step 6: Now subtract the tens: 6 - 2 = 4 Step 7: Combine the tens and ones: 4 tens and 7 ones = 47 Step 8: Conclusion: Lily has 47 stickers left. Answer: 47

10. Charlotte has 72 beads. She uses 35 beads to make a bracelet. How many beads does she have left? Answer: 37 Solution: Start with 72 beads. Step 2: Subtract the 35 beads used: 72 - 35. Step 3: Break into tens and ones: 72 = 70 + 2, 35 = 30 + 5.
    Full step-by-step solution

    Step 1: Start with 72 beads. Step 2: Subtract the 35 beads used: 72 - 35. Step 3: Break into tens and ones: 72 = 70 + 2, 35 = 30 + 5. Step 4: Subtract tens: 70 - 30 = 40. Step 5: Subtract ones: 2 - 5 cannot be done, so borrow 1 ten from 40 to make 12 ones. Now 40 becomes 30, and 12 - 5 = 7. Step 6: Add the tens and ones: 30 + 7 = 37. The answer is 37.