Multiply 4-Digit by 1-Digit

lessonbunny.com

Answer Key & Explanations

Multiply 4-Digit by 1-Digit · Grade 4 · Worksheet 3

1. A rectangular swimming pool is drawn with a length of 25 meters and a width of 12 meters. The pool is surrounded by a tile border that is 2 meters wide on all sides. What is the total area of the pool including the tile border? Answer: 464 Solution: The pool itself has length 25 m and width 12 m. The border adds 2 meters to both the left and right sides, so it adds 4 meters to the total length: 25 + 4 = 29 m.
   Full step-by-step solution

   Step 1: The pool itself has length 25 m and width 12 m. Step 2: The border adds 2 meters to both the left and right sides, so it adds 4 meters to the total length: 25 + 4 = 29 m. Step 3: The border adds 2 meters to both the top and bottom, so it adds 4 meters to the total width: 12 + 4 = 16 m. Step 4: Calculate the total area: length × width = 29 × 16. Step 5: Multiply: 29 × 10 = 290, and 29 × 6 = 174. Step 6: Add: 290 + 174 = 464. The total area including the tile border is 464 square meters.

2. A community center is organizing a summer reading program and needs to order books for 24 reading groups. Each group will receive 156 books to share among their members. How many books does the community center need to order in total? Answer: 3744 Solution: Identify the number of groups: 24 reading groups Identify the number of books per group: 156 books Multiply to find the total number of books: 24 × 156 Calculate 24 × 100 = 2400 Calculate 24 × 50 = 1200 Calculate 24 × 6 = 144 Add the partial products: 2400 + 1200 = 3600, then 3600 + 144 = 3744…
   Full step-by-step solution

   Step 1: Identify the number of groups: 24 reading groups Step 2: Identify the number of books per group: 156 books Step 3: Multiply to find the total number of books: 24 × 156 Step 4: Calculate 24 × 100 = 2400 Step 5: Calculate 24 × 50 = 1200 Step 6: Calculate 24 × 6 = 144 Step 7: Add the partial products: 2400 + 1200 = 3600, then 3600 + 144 = 3744 Step 8: The community center needs to order 3744 books in total.

3. A school is organizing a field trip and needs to order buses. Each bus can carry 48 students. If there are 325 students going on the trip, how many buses are needed to transport all the students? Answer: 7 Solution: We have 325 students, and each bus can carry 48 students. We need to find how many buses are needed to transport all students. Divide the total number of students by the bus capacity.
   Full step-by-step solution

   Step 1: Understand the problem. We have 325 students, and each bus can carry 48 students. We need to find how many buses are needed to transport all students. Step 2: Divide the total number of students by the bus capacity. 325 ÷ 48 = ? Step 3: Perform the division. 48 × 6 = 288 325 − 288 = 37 So, 325 ÷ 48 = 6 remainder 37. Step 4: Interpret the result. 6 full buses will carry 288 students, but there are 37 students left over. These 37 students also need a bus, so we need one more bus for them. Step 5: Determine the total number of buses. 6 buses + 1 bus = 7 buses. Step 6: Check the answer. 7 buses × 48 students = 336 seats, which is enough for 325 students. 6 buses would only hold 288 students, which is not enough. Final answer: 7 buses are needed.

4. A farmer plants corn in a rectangular field that measures 125 meters long and 80 meters wide. If she plants 4 corn plants per square meter, how many corn plants are in the entire field? Answer: 40000 Solution: First, find the area of the rectangular field. Area = length × width Area = 125 meters × 80 meters Area = 10000 square meters Next, multiply the area by the number of corn plants per square meter.
   Full step-by-step solution

   First, find the area of the rectangular field. Area = length × width Area = 125 meters × 80 meters Area = 10000 square meters Next, multiply the area by the number of corn plants per square meter. Number of plants = area × plants per square meter Number of plants = 10000 × 4 Number of plants = 40000 So, the total number of corn plants in the entire field is 40000.

5. A school is organizing a field trip and needs to buy snacks for all 348 students. If each student receives 4 cookies, how many cookies does the school need to buy in total? Answer: 1392 Solution: We have 348 students, and each student gets 4 cookies. We need to find the total number of cookies. Identify the operation.
   Full step-by-step solution

   Step 1: Understand the problem. We have 348 students, and each student gets 4 cookies. We need to find the total number of cookies. Step 2: Identify the operation. Since each student gets the same number of cookies, we multiply the number of students by the number of cookies per student. Step 3: Write the multiplication. Total cookies = 348 × 4 Step 4: Break down the multiplication. First, multiply 4 by the ones digit of 348: 4 × 8 = 32 Write down 2, carry over 3. Step 5: Multiply 4 by the tens digit of 348: 4 × 4 = 16 Add the carried over 3: 16 + 3 = 19 Write down 9, carry over 1. Step 6: Multiply 4 by the hundreds digit of 348: 4 × 3 = 12 Add the carried over 1: 12 + 1 = 13 Write down 13. Step 7: Combine the digits. From steps 4–6, we have: 13, then 9, then 2 → 1392. Step 8: Conclusion. The school needs to buy 1392 cookies in total.

6. A factory produces 1,245 toy cars each day. If the factory operates for 23 days this month, how many toy cars will it produce in total? Answer: 28635 Solution: The factory produces 1,245 toy cars each day and operates for 23 days.
   Full step-by-step solution

   Step 1: The factory produces 1,245 toy cars each day and operates for 23 days. Step 2: To find the total number of toy cars, multiply the daily production by the number of days: 1,245 × 23 Step 3: First, multiply 1,245 by 20: 1,245 × 20 = 24,900 Step 4: Then, multiply 1,245 by 3: 1,245 × 3 = 3,735 Step 5: Add the two results together: 24,900 + 3,735 = 28,635 Step 6: The factory will produce 28,635 toy cars in total this month.