Rounding Numbers

lessonbunny.com

Answer Key & Explanations

Rounding Numbers · Grade 3 · Worksheet 1

1. Emma is planning a school field trip for her class. There are 28 students in her class and 4 teachers going on the trip. Each school bus can hold 32 people. How many buses are needed for the field trip? Answer: 1 Solution: Students: 28 Teachers: 4 Total people = 28 + 4 = 32 Each bus holds 32 people Total people ÷ People per bus = 32 ÷ 32 = 1 One bus can hold exactly 32 people, and we have exactly 32 people going on the trip.
   Full step-by-step solution

   Step 1: Find the total number of people going on the trip Students: 28 Teachers: 4 Total people = 28 + 4 = 32 Step 2: Determine how many buses are needed Each bus holds 32 people Total people ÷ People per bus = 32 ÷ 32 = 1 Step 3: Check if this makes sense One bus can hold exactly 32 people, and we have exactly 32 people going on the trip. The answer is 1 bus.

2. Round 6876 to the nearest 100. Answer: 6900 Solution: Look at the digit that decides rounding to the nearest 100. 6876 rounds to 6900.
   Full step-by-step solution

   Step 1: Look at the digit that decides rounding to the nearest 100. Step 2: 6876 rounds to 6900. The answer is 6900.

3. Round 853 to the nearest 10. Answer: 850 Solution: Look at the digit that decides rounding to the nearest 10. 853 rounds to 850.
   Full step-by-step solution

   Step 1: Look at the digit that decides rounding to the nearest 10. Step 2: 853 rounds to 850. The answer is 850.

4. A rectangular garden is drawn with a length of 85 meters and a width of 40 meters. What is the total distance around the garden? Answer: 250 Solution: We are told the garden is rectangular with length 85 meters and width 40 meters. The "total distance around" means the perimeter of the rectangle. Recall the formula for the perimeter of a rectangle.
   Full step-by-step solution

   Step 1: Understand the problem. We are told the garden is rectangular with length 85 meters and width 40 meters. The "total distance around" means the perimeter of the rectangle. Step 2: Recall the formula for the perimeter of a rectangle. Perimeter = 2 × (length + width) Step 3: Substitute the given values into the formula. Length = 85 m, Width = 40 m Perimeter = 2 × (85 + 40) Step 4: Perform the addition inside the parentheses. 85 + 40 = 125 Step 5: Multiply by 2. 2 × 125 = 250 Step 6: State the final answer with units. The total distance around the garden is 250 meters.

5. 64 + 37 = ? Answer: 101 Solution: Write the numbers vertically in your mind for alignment by place value. 64 + 37 Start by adding the digits in the ones column (rightmost column). Ones column: 4 + 7 = 11.
   Full step-by-step solution

   Let's add 64 and 37 step-by-step. Step 1: Write the numbers vertically in your mind for alignment by place value. 64 + 37 Step 2: Start by adding the digits in the ones column (rightmost column). Ones column: 4 + 7 = 11. 11 is a two-digit number, so we split it: 11 = 10 + 1. We write down the 1 in the ones place of the answer and carry over the 10 (which is 1 ten) to the tens column. Step 3: Now add the tens column, including the carry-over. Tens column: 6 (from 64) + 3 (from 37) + 1 (carried over) = 10. So the tens column sum is 10 tens, which is 100. Step 4: Combine the results from the tens and ones columns. From Step 3: 10 tens = 100 From Step 2: 1 one = 1 So total = 100 + 1 = 101. Final answer: 101

6. Noah is helping his teacher set up chairs for the school concert. They have 95 chairs to arrange in rows. If each row can hold 10 chairs, how many complete rows can Noah make? Answer: 9 Solution: Noah has 95 chairs total. Each row holds 10 chairs. To find how many complete rows, divide 95 by 10.
   Full step-by-step solution

   Step 1: Noah has 95 chairs total. Step 2: Each row holds 10 chairs. Step 3: To find how many complete rows, divide 95 by 10. Step 4: 95 ÷ 10 = 9 with a remainder of 5. Step 5: The question asks for complete rows, so we use the whole number part of the answer. Noah can make 9 complete rows of chairs.

7. 1000 - 350 = ? Answer: 650 Solution: Write the problem vertically to make it easier. 1000 - 350 Start subtracting from the rightmost column (ones place). The top number in the ones place is 0, and the bottom number is 0.
   Full step-by-step solution

   Let's solve 1000 - 350 step by step. Step 1: Write the problem vertically to make it easier. 1000 - 350 _______ Step 2: Start subtracting from the rightmost column (ones place). The top number in the ones place is 0, and the bottom number is 0. 0 - 0 = 0 Write 0 in the ones place of the answer. Step 3: Move to the tens place. The top number is 0, and the bottom number is 5. We cannot do 0 - 5 because 0 is smaller than 5. So we need to borrow. Step 4: Look to the hundreds place. The hundreds digit in 1000 is 0, so we cannot borrow from there directly. We must go to the thousands place. Step 5: Borrow from the thousands place: - The thousands place digit is 1 (meaning 1000). - We take 1 thousand and change it into 10 hundreds. - So now the thousands place becomes 0, and the hundreds place becomes 10. But the hundreds digit was 0, now it's 10. Step 6: Now, from these 10 hundreds, we can borrow 1 hundred for the tens place. - 10 hundreds become 9 hundreds (in the hundreds place). - The 1 hundred we borrow becomes 10 tens in the tens place. - The tens place was 0, now it becomes 10. Step 7: Now subtract in the tens place: Tens place: 10 (after borrowing) - 5 = 5. Write 5 in the tens place of the answer. Step 8: Move to the hundreds place: Hundreds place: 9 (after lending to tens) - 3 = 6. Write 6 in the hundreds place of the answer. Step 9: Move to the thousands place: Thousands place: 0 (after lending to hundreds) - 0 = 0. Since this is the leading digit, we don't write it. So the result is 650. Final check: 1000 - 350 = 650.

8. 1000 - 675 = ? Answer: 325 Solution: Start with 1000 Subtract 600: 1000 - 600 = 400 Subtract 75: 400 - 75 = 325 Check: 325 + 675 = 1000 The answer is 325.
   Full step-by-step solution

   Step 1: Start with 1000 Step 2: Subtract 600: 1000 - 600 = 400 Step 3: Subtract 75: 400 - 75 = 325 Step 4: Check: 325 + 675 = 1000 The answer is 325.