Estimate Lengths

lessonbunny.com

Answer Key & Explanations

Estimate Lengths · Grade 2 · Worksheet 3

1. Mason is trying to estimate the length of his new bookshelf. He thinks it is about as long as 4 of his arm lengths. If Mason's arm is about 15 inches long, about how many inches long is his bookshelf? Answer: About 60 inches Solution: Mason is estimating the length of his bookshelf. He knows his arm is about 15 inches long. He thinks the bookshelf is about 4 arm lengths long.
   Full step-by-step solution

   Step 1: Understand the problem. Mason is estimating the length of his bookshelf. He knows his arm is about 15 inches long. He thinks the bookshelf is about 4 arm lengths long. Step 2: To estimate, we can add 15 inches four times: 15 + 15 + 15 + 15. Step 3: Add the first two: 15 + 15 = 30. Step 4: Add the next two: 15 + 15 = 30. Step 5: Add those two totals together: 30 + 30 = 60. Step 6: So, a good estimate for the length of the bookshelf is about 60 inches. The answer is about 60 inches.

2. Emma's desk is about 5 feet long. She wants to estimate the length of her teacher's desk, which she thinks is much longer. If Emma's desk is 5 feet, about how many feet long do you think her teacher's desk might be? Answer: About 7 feet Solution: Emma's desk is about 5 feet long. Step 2: A teacher's desk is usually a bit longer than a student's desk. Step 3: A reasonable estimate might be about 2 feet longer, which gives 5 + 2 = 7 feet.
   Full step-by-step solution

   Step 1: Emma's desk is about 5 feet long. Step 2: A teacher's desk is usually a bit longer than a student's desk. Step 3: A reasonable estimate might be about 2 feet longer, which gives 5 + 2 = 7 feet. Step 4: So, the teacher's desk is about 7 feet long. The answer is about 7 feet.

3. Kaia estimates that her desk is about 45 centimeters long. About how many centimeters long is her desk? Answer: 45 centimeters Solution: Read the problem carefully. Kaia is estimating the length of her desk. Step 2: The problem tells us that Kaia's estimate is 'about 45 centimeters long.' Step 3: Since the question asks 'About how many centimeters long is her desk?' and the estimate is given as 45 centimeters, the answer is the…
   Full step-by-step solution

   Step 1: Read the problem carefully. Kaia is estimating the length of her desk. Step 2: The problem tells us that Kaia's estimate is 'about 45 centimeters long.' Step 3: Since the question asks 'About how many centimeters long is her desk?' and the estimate is given as 45 centimeters, the answer is the same as the estimate. Step 4: So, her desk is about 45 centimeters long. Final answer: 45 centimeters.

4. Emma is collecting seashells at the beach. On Monday, she found 28 shells. On Tuesday, she found 35 more shells. How many seashells does Emma have in total? Answer: 63 seashells Solution: Emma found 28 shells on Monday. Emma found 35 shells on Tuesday.
   Full step-by-step solution

   Step 1: Emma found 28 shells on Monday. Step 2: Emma found 35 shells on Tuesday. Step 3: Add the shells from both days: 28 + 35 Step 4: First, add the ones: 8 + 5 = 13 (write down 3, carry over 1 to the tens) Step 5: Then, add the tens: 2 + 3 + 1 = 6 Step 6: Combine the tens and ones: 60 + 3 = 63 Emma has 63 seashells in total.

5. Emma is collecting seashells at the beach. On Monday, she found 28 seashells. On Tuesday, she found 35 more seashells. How many seashells did Emma find in total? Answer: 63 seashells Solution: Emma found 28 seashells on Monday. Emma found 35 seashells on Tuesday.
   Full step-by-step solution

   Step 1: Emma found 28 seashells on Monday. Step 2: Emma found 35 seashells on Tuesday. Step 3: Add the seashells from both days: 28 + 35 Step 4: First add the ones: 8 + 5 = 13 (write down 3, carry over 1 to the tens place) Step 5: Then add the tens: 2 + 3 + 1 = 6 Step 6: Combine the tens and ones: 60 + 3 = 63 Emma found 63 seashells in total.

6. Noah's desk is about 61 centimeters long. Estimate: About how many centimeters long is Noah's desk? Answer: 61 centimeters Solution: Read the problem carefully. It says Noah's desk is about 61 centimeters long. The word 'about' tells us this is already an estimate, not an exact measurement.
   Full step-by-step solution

   Step 1: Read the problem carefully. It says Noah's desk is about 61 centimeters long. Step 2: The word 'about' tells us this is already an estimate, not an exact measurement. Step 3: The question asks us to estimate the length. Since the problem already gives an estimate of 61 centimeters, we can use that number. Step 4: So, the estimated length of Noah's desk is 61 centimeters. Final answer: 61 centimeters.

7. Isabella is looking at her new bookshelf. She wants to estimate how tall it is. If she knows that a typical door is about 7 feet tall, and her bookshelf is a little shorter than the door, about how many feet tall is Isabella's bookshelf? Answer: About 6 feet Solution: We know a typical door is about 7 feet tall. The problem says the bookshelf is a little shorter than the door. A reasonable estimate for something a little shorter than 7 feet is about 6 feet.
   Full step-by-step solution

   Step 1: We know a typical door is about 7 feet tall. Step 2: The problem says the bookshelf is a little shorter than the door. Step 3: A reasonable estimate for something a little shorter than 7 feet is about 6 feet. Step 4: So, Isabella's bookshelf is about 6 feet tall. The answer is about 6 feet.

8. Liam is building a tower with blocks. He used 32 red blocks and 45 blue blocks. How many blocks did Liam use in total? Answer: 77 Solution: Identify the number of red blocks and blue blocks. Liam used 32 red blocks and 45 blue blocks. Understand that to find the total number of blocks, we need to add the number of red blocks and blue blocks together.
   Full step-by-step solution

   Step 1: Identify the number of red blocks and blue blocks. Liam used 32 red blocks and 45 blue blocks. Step 2: Understand that to find the total number of blocks, we need to add the number of red blocks and blue blocks together. So, total blocks = red blocks + blue blocks. Step 3: Perform the addition. 32 + 45 First, add the ones place: 2 + 5 = 7. Then, add the tens place: 3 + 4 = 7. So, 32 + 45 = 77. Step 4: State the final answer. Liam used 77 blocks in total.

9. Lily has 28 crayons in her box. Her teacher gives her 15 more crayons for art class. How many crayons does Lily have now? Answer: 43 Solution: Lily starts with 28 crayons. Her teacher gives her 15 more crayons. We need to find the total number of crayons she has now.
   Full step-by-step solution

   Step 1: Understand the problem. Lily starts with 28 crayons. Her teacher gives her 15 more crayons. We need to find the total number of crayons she has now. Step 2: Write the addition expression. Starting crayons: 28 Additional crayons: 15 Total crayons = 28 + 15 Step 3: Add the numbers. First, add the ones place: 8 + 5 = 13. Write down 3 in the ones place and carry over 1 to the tens place. Step 4: Add the tens place. Tens place: 2 + 1 = 3, plus the carried over 1 makes 4. So the tens place is 4. Step 5: Combine the digits. Tens place: 4, Ones place: 3 So 28 + 15 = 43. Step 6: State the final answer. Lily now has 43 crayons.