Estimation

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Estimation · Grade 3 · Worksheet 1

1. Liam is collecting cans for recycling. On Monday, he collected 127 cans. On Tuesday, he collected 94 cans. About how many cans did Liam collect in total? Round each number to the nearest ten before adding. Answer: 220 Solution: Identify the numbers given in the problem. Liam collected 127 cans on Monday and 94 cans on Tuesday. Round each number to the nearest ten.
   Full step-by-step solution

   Step 1: Identify the numbers given in the problem. Liam collected 127 cans on Monday and 94 cans on Tuesday. Step 2: Round each number to the nearest ten. - 127: The digit in the ones place is 7, which is 5 or more, so we round up. 127 rounded to the nearest ten is 130. - 94: The digit in the ones place is 4, which is less than 5, so we round down. 94 rounded to the nearest ten is 90. Step 3: Add the rounded numbers. 130 + 90 = 220. Step 4: State the final answer. So, Liam collected about 220 cans in total.

2. Emma is reading a book with 328 pages. She read 187 pages on Monday and plans to read the rest on Tuesday. About how many pages does Emma have left to read? Round each number to the nearest hundred before estimating. Answer: 100 Solution: Round 328 to the nearest hundred: 328 is closer to 300 than 400, so 328 ≈ 300 Round 187 to the nearest hundred: 187 is closer to 200 than 100, so 187 ≈ 200 Estimate the remaining pages: 300 - 200 = 100 Emma has about 100 pages left to read.
   Full step-by-step solution

   Step 1: Round 328 to the nearest hundred: 328 is closer to 300 than 400, so 328 ≈ 300 Step 2: Round 187 to the nearest hundred: 187 is closer to 200 than 100, so 187 ≈ 200 Step 3: Estimate the remaining pages: 300 - 200 = 100 Emma has about 100 pages left to read.

3. A rectangular swimming pool is drawn with a length of 125 meters and a width of 75 meters. What is the perimeter of the swimming pool? Answer: 400 meters Solution: The perimeter of a rectangle is calculated by adding all four sides together. The formula for perimeter of a rectangle is: Perimeter = 2 × (length + width) Substitute the given values: Perimeter = 2 × (125 + 75) First, add the length and width: 125 + 75 = 200 Then multiply by 2: 2 × 200 = 400…
   Full step-by-step solution

   Step 1: The perimeter of a rectangle is calculated by adding all four sides together. Step 2: The formula for perimeter of a rectangle is: Perimeter = 2 × (length + width) Step 3: Substitute the given values: Perimeter = 2 × (125 + 75) Step 4: First, add the length and width: 125 + 75 = 200 Step 5: Then multiply by 2: 2 × 200 = 400 Step 6: The perimeter of the swimming pool is 400 meters.

4. Noah is organizing a school fundraiser. He collected 347 toy cars for the toy drive and 182 stuffed animals. About how many toys did Noah collect in total? Round each number to the nearest hundred before estimating the sum. Answer: 500 Solution: Round 347 to the nearest hundred. The tens digit is 4, which is less than 5, so 347 rounds down to 300. Round 182 to the nearest hundred.
   Full step-by-step solution

   Step 1: Round 347 to the nearest hundred. The tens digit is 4, which is less than 5, so 347 rounds down to 300. Step 2: Round 182 to the nearest hundred. The tens digit is 8, which is 5 or greater, so 182 rounds up to 200. Step 3: Add the rounded numbers: 300 + 200 = 500. The estimated total number of toys is 500.

5. 245 + 387 = ? Answer: 632 Solution: Write the numbers one above the other, aligning the digits by place value (ones, tens, hundreds). 245 387 Add the ones column (rightmost column). 5 + 7 = 12 12 is 10 + 2.
   Full step-by-step solution

   Let's add 245 and 387 step-by-step. Step 1: Write the numbers one above the other, aligning the digits by place value (ones, tens, hundreds). 245 387 --- Step 2: Add the ones column (rightmost column). 5 + 7 = 12 12 is 10 + 2. Write down the 2 in the ones place of the answer, and carry over the 1 (which is 1 ten) to the tens column. Answer so far: ___2 Carry: 1 Step 3: Add the tens column (middle column). We have: 4 + 8 + the carried 1 = 13 13 is 10 + 3. Write down the 3 in the tens place of the answer, and carry over the 1 (which is 1 hundred) to the hundreds column. Answer so far: __32 Carry: 1 Step 4: Add the hundreds column (leftmost column). We have: 2 + 3 + the carried 1 = 6 Write down the 6 in the hundreds place. Answer so far: 632 Step 5: Final check. 245 + 387 = 632. Therefore, the correct answer is 632.

6. Estimate: 462 + 538 (round to nearest 100) Answer: 1000 Solution: Round 462 to the nearest 100. 462 is between 400 and 500. Since the tens digit is 6 (which is 5 or more), round up to 500.
   Full step-by-step solution

   Step 1: Round 462 to the nearest 100. 462 is between 400 and 500. Since the tens digit is 6 (which is 5 or more), round up to 500. Step 2: Round 538 to the nearest 100. 538 is between 500 and 600. Since the tens digit is 3 (which is less than 5), round down to 500. Step 3: Add the rounded numbers: 500 + 500 = 1000. The estimated sum is 1000.

7. A farmer harvested 3,845 apples from one orchard and 2,957 apples from another orchard. About how many apples did the farmer harvest in total? Round each number to the nearest hundred before adding. Answer: 6800 Solution: Identify the numbers to round. We have 3,845 and 2,957. Round each number to the nearest hundred.
   Full step-by-step solution

   Step 1: Identify the numbers to round. We have 3,845 and 2,957. Step 2: Round each number to the nearest hundred. - 3,845: Look at the tens digit, which is 4. Since 4 is less than 5, we round down. So 3,845 rounded to the nearest hundred is 3,800. - 2,957: Look at the tens digit, which is 5. Since it is 5 or greater, we round up. So 2,957 rounded to the nearest hundred is 3,000. Step 3: Add the rounded numbers. 3,800 + 3,000 = 6,800. Step 4: State the final answer. The farmer harvested about 6,800 apples in total.