Estimate Lengths

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Answer Key & Explanations

Estimate Lengths · Grade 2 · Worksheet 1

1. Noah's desk is about 7 feet long. About how many inches long is his desk? Answer: 84 inches Solution: Recall that 1 foot = 12 inches. Since Noah's desk is about 7 feet long, multiply the number of feet by the number of inches in each foot. 7 × 12 = 84 So, Noah's desk is about 84 inches long.
   Full step-by-step solution

   Step 1: Recall that 1 foot = 12 inches. Step 2: Since Noah's desk is about 7 feet long, multiply the number of feet by the number of inches in each foot. Step 3: 7 × 12 = 84 Step 4: So, Noah's desk is about 84 inches long. Final answer: 84 inches.

2. 25 + 38 = ? Answer: 63 Solution: Write the numbers vertically in your mind, aligning the digits by place value (ones and tens). 25 + 38 Add the digits in the ones column first (rightmost column).
   Full step-by-step solution

   Let's add 25 and 38 step by step. Step 1: Write the numbers vertically in your mind, aligning the digits by place value (ones and tens). 25 + 38 Step 2: Add the digits in the ones column first (rightmost column). 5 + 8 = 13 Step 3: Since 13 is a two-digit number, we separate it into 1 ten and 3 ones. Write down the 3 in the ones place of the answer, and carry over the 1 ten to the tens column. Step 4: Now add the digits in the tens column, including the carry-over. 2 (from 25) + 3 (from 38) + 1 (carried over) = 6 Step 5: Write the 6 in the tens place of the answer. Step 6: Combine the tens digit and ones digit: 6 tens and 3 ones makes 63. Final answer: 63

3. Mere estimates that her classroom door is about how many centimeters tall? Answer: 200 centimeters Solution: Think about the height of a typical classroom door. Most classroom doors are about 2 meters tall. Since 1 meter equals 100 centimeters, multiply 2 by 100.
   Full step-by-step solution

   Step 1: Think about the height of a typical classroom door. Most classroom doors are about 2 meters tall. Step 2: Since 1 meter equals 100 centimeters, multiply 2 by 100. Step 3: 2 × 100 = 200. Step 4: So, a good estimate for the height of a classroom door is 200 centimeters. Final answer: 200 centimeters.

4. Noah is looking at a new bookshelf in his classroom. He knows that a typical ruler is 12 inches long. About how many rulers long do you think the bookshelf might be if it is around 72 inches long? Answer: About 6 rulers Solution: The bookshelf is about 72 inches long. One ruler is 12 inches long. To find about how many rulers long the bookshelf is, think: 72 inches divided by 12 inches per ruler equals 6 rulers.
   Full step-by-step solution

   Step 1: The bookshelf is about 72 inches long. Step 2: One ruler is 12 inches long. Step 3: To find about how many rulers long the bookshelf is, think: 72 inches divided by 12 inches per ruler equals 6 rulers. Step 4: So the bookshelf is about 6 rulers long. Answer: About 6 rulers.

5. A carpenter has a board that is 72 centimeters long. She cuts off a piece that is 35 centimeters long. How many centimeters of board are left? Answer: 37 centimeters Solution: Start with the original board length: 72 centimeters Subtract the length that was cut off: 72 - 35 Calculate 72 - 35: First subtract the ones: 2 - 5 (can't do), so borrow from tens: 12 - 5 = 7 Now subtract the tens: 6 - 3 = 3 (since we borrowed 1 from the 7) Combine the results: 3 tens and 7…
   Full step-by-step solution

   Step 1: Start with the original board length: 72 centimeters Step 2: Subtract the length that was cut off: 72 - 35 Step 3: Calculate 72 - 35: First subtract the ones: 2 - 5 (can't do), so borrow from tens: 12 - 5 = 7 Step 4: Now subtract the tens: 6 - 3 = 3 (since we borrowed 1 from the 7) Step 5: Combine the results: 3 tens and 7 ones = 37 The answer is 37 centimeters.

6. Isabella's new bookshelf is about 8 feet tall. She wants to estimate if her 6-foot tall toy castle will fit on the top shelf. About how many feet tall is the bookshelf? Answer: About 8 feet Solution: The problem says the bookshelf is 'about 8 feet tall.' This means 8 feet is an estimate of the bookshelf's height.
   Full step-by-step solution

   Step 1: The problem says the bookshelf is 'about 8 feet tall.' This means 8 feet is an estimate of the bookshelf's height. Step 2: The question asks, 'About how many feet tall is the bookshelf?' Step 3: We use the information given: the bookshelf is about 8 feet tall. So the estimate is 8 feet. Final answer: About 8 feet.

7. Liam is building a tower with blocks. He used 24 red blocks and 37 blue blocks. How many blocks did Liam use in total? Answer: 61 Solution: Identify the number of red blocks and blue blocks. Liam used 24 red blocks and 37 blue blocks. Understand that to find the total number of blocks, we need to add the red blocks and blue blocks together.
   Full step-by-step solution

   Step 1: Identify the number of red blocks and blue blocks. Liam used 24 red blocks and 37 blue blocks. Step 2: Understand that to find the total number of blocks, we need to add the red blocks and blue blocks together. So, total blocks = red blocks + blue blocks. Step 3: Write the addition expression. Total blocks = 24 + 37. Step 4: Add the numbers. First, add the ones place: 4 + 7 = 11. Write down 1 in the ones place and carry over 1 to the tens place. Step 5: Add the tens place: 2 + 3 = 5, plus the carried over 1 gives 6. So, the tens place is 6. Step 6: Combine the digits: 6 tens and 1 one gives 61. Step 7: State the final answer. Liam used 61 blocks in total.

8. Emma is collecting stickers for her album. She has 48 animal stickers and 25 flower stickers. How many stickers does Emma have in total? Answer: 73 stickers Solution: Emma has 48 animal stickers She also has 25 flower stickers Add the two amounts together: 48 + 25 Add the ones place: 8 + 5 = 13 (write down 3, carry over 1) Add the tens place: 4 + 2 + 1 = 7 Combine the results: 73 Emma has 73 stickers in total.
   Full step-by-step solution

   Step 1: Emma has 48 animal stickers Step 2: She also has 25 flower stickers Step 3: Add the two amounts together: 48 + 25 Step 4: Add the ones place: 8 + 5 = 13 (write down 3, carry over 1) Step 5: Add the tens place: 4 + 2 + 1 = 7 Step 6: Combine the results: 73 Emma has 73 stickers in total.

9. Mere estimates that her desk is about 80 centimeters long. About how many centimeters long is Mere's desk? Answer: 80 centimeters Solution: Read the problem carefully. It says Mere estimates her desk is about 80 centimeters long. The word 'estimate' means a reasonable guess.
   Full step-by-step solution

   Step 1: Read the problem carefully. It says Mere estimates her desk is about 80 centimeters long. Step 2: The word 'estimate' means a reasonable guess. Mere's guess is 80 centimeters. Step 3: The question asks: 'About how many centimeters long is Mere's desk?' The answer is the estimate she gave. Final answer: 80 centimeters.