Multi-step word problems.
Subtopic Navigator
- Introduction to Multi-Step Word Problems
- Problem Solving Strategies
- Addition and Subtraction Multi-Step Problems
- Multiplication and Division Multi-Step Problems
- Mixed Operations Problems
- Methods & Techniques
- Common Mistakes & Misconceptions
- Real-World Applications
- Practice Exercises
- Conclusion & Summary
Lesson Objectives
- Read and understand multi-step word problems carefully
- Identify the steps needed to solve a problem
- Choose the correct operations (addition, subtraction, multiplication, division)
- Solve problems in the correct order
- Check answers for reasonableness using estimation
- Apply problem-solving strategies to real-world situations
Introduction to Multi-Step Word Problems
Multi-step word problems require more than one mathematical operation to find the answer. They help us solve real-life situations that involve several steps, such as shopping, budgeting, cooking, or planning a trip. Solving these problems builds critical thinking and prepares you for more advanced mathematics.
A problem that requires two or more operations (addition, subtraction, multiplication, division) to find the final answer.
• Multi-step problem: A problem that requires more than one mathematical operation to solve.
• Operation: Addition, subtraction, multiplication, or division.
• Hidden question: An intermediate answer needed before finding the final answer.
• Reasonable answer: An answer that makes sense based on estimation and context.
Problem Solving Strategies
Solving multi-step word problems requires a systematic approach. The following strategies will help you break down complex problems into manageable steps.
1. Read the problem carefully: Understand what is being asked.
2. Identify what is known: List all the given information.
3. Identify what is unknown: What do you need to find?
4. Determine the hidden questions: What intermediate answers do you need?
5. Plan the steps: Decide which operations to use and in what order.
6. Solve step by step: Perform each calculation carefully.
7. Check your answer: Is it reasonable? Does it make sense in the context?
8. Write the final answer: Include units and a complete sentence.
| Step | Action | Question to Ask |
|---|---|---|
| 1 | Read | What is the problem asking? |
| 2 | Identify | What information is given? |
| 3 | Plan | What steps are needed? |
| 4 | Solve | Perform calculations in order |
| 5 | Check | Does my answer make sense? |
Problem: Sarah bought a shirt for ₦2,500 and a pair of shoes for ₦4,500. She gave the cashier ₦10,000. How much change did she receive?
Solution using the method:
Step 1: Read carefully → Need to find change.
Step 2: Known: shirt = ₦2,500, shoes = ₦4,500, paid = ₦10,000.
Step 3: Plan: First find total cost, then subtract from amount paid.
Step 4: Total = 2,500 + 4,500 = 7,000; Change = 10,000 - 7,000 = 3,000.
Step 5: Check: 7,000 + 3,000 = 10,000 ✓
Answer: Sarah received ₦3,000 change.
Don't rush! Read the problem at least twice before starting. Look for clue words that indicate which operation to use.
Practice for Problem Solving Strategies
- List the steps you would take to solve: "John had 120 oranges. He sold 45 on Monday and 38 on Tuesday. How many are left?"
- What is the hidden question in: "A baker bakes 24 loaves per hour. He works for 6 hours. He sells 85 loaves. How many are left?"
- Why is it important to check your answer after solving a multi-step problem?
Addition and Subtraction Multi-Step Problems
Many multi-step problems involve only addition and subtraction. These problems often ask for totals, differences, or remaining amounts after several changes.
Problem: A school bought 345 notebooks, 278 pencils, and 156 erasers. How many items did they buy in total?
Solution:
Step 1: Add notebooks and pencils: 345 + 278 = 623
Step 2: Add erasers: 623 + 156 = 779
Answer: The school bought 779 items.
Problem: Mrs. Ade had ₦15,000. She spent ₦4,500 on food, ₦3,200 on transport, and ₦2,800 on clothes. How much money does she have left?
Solution:
Step 1: Find total spent: 4,500 + 3,200 = 7,700; 7,700 + 2,800 = 10,500
Step 2: Subtract from starting amount: 15,000 - 10,500 = 4,500
Answer: Mrs. Ade has ₦4,500 left.
Problem: Town A has 45,678 people. Town B has 32,456 fewer people than Town A. Town C has 12,345 more people than Town B. What is the population of Town C?
Solution:
Step 1: Find Town B population: 45,678 - 32,456 = 13,222
Step 2: Find Town C population: 13,222 + 12,345 = 25,567
Answer: Town C has 25,567 people.
When a problem says "fewer than," you subtract. When it says "more than," you add. Pay attention to the order!
Practice for Addition and Subtraction Multi-Step Problems
- A shop sold 234 bags of rice on Monday, 187 on Tuesday, and 256 on Wednesday. How many bags were sold in total?
- A man had ₦50,000. He paid ₦12,500 for rent, ₦8,750 for food, and ₦5,250 for electricity. How much is left?
- City X has 234,567 people. City Y has 45,678 fewer people. City Z has 23,456 more than City Y. Find City Z's population.
- A library had 12,345 books. They received 2,500 new books and then donated 1,200 books. How many books are now in the library?
- A car travelled 234 km, then another 156 km, then 89 km. How far did it travel in total?
Multiplication and Division Multi-Step Problems
Some multi-step problems involve multiplication and division. These often include finding totals from equal groups, sharing equally, or calculating rates.
Problem: A factory produces 234 bottles per hour. How many bottles are produced in 8 hours?
Solution:
234 × 8 = 1,872 bottles
Answer: 1,872 bottles
Problem: A school ordered 24 boxes of notebooks. Each box contains 50 notebooks. If 345 notebooks were damaged, how many good notebooks are there?
Solution:
Step 1: Find total notebooks: 24 × 50 = 1,200
Step 2: Subtract damaged: 1,200 - 345 = 855
Answer: 855 good notebooks.
Problem: 1,260 oranges are to be packed equally into 30 crates. How many oranges are in each crate?
Solution:
1,260 ÷ 30 = 42 oranges per crate
Answer: 42 oranges
Problem: A car travels 480 km on 40 litres of fuel. How far can it travel on 25 litres?
Solution:
Step 1: Find distance per litre: 480 ÷ 40 = 12 km per litre
Step 2: Find distance for 25 litres: 12 × 25 = 300 km
Answer: 300 km
In problems involving rates (like km per litre, cost per item), always find the unit rate first (how much per one unit).
Practice for Multiplication and Division Multi-Step Problems
- A bakery bakes 156 loaves of bread per hour. How many loaves in 12 hours?
- A school has 28 classes with 35 students in each class. If 120 students are absent, how many are present?
- 3,600 eggs are packed equally into 120 cartons. How many eggs in each carton?
- A car travels 540 km on 45 litres of fuel. How far on 30 litres?
- A farmer harvested 2,400 kg of rice. He packs it into 80 kg bags. How many bags does he fill?
Mixed Operations Problems
The most challenging multi-step problems combine all four operations: addition, subtraction, multiplication, and division. These problems require careful planning and attention to order.
Problem: Mr. John bought 5 shirts at ₦3,500 each and 3 pairs of trousers at ₦5,000 each. He paid with ₦50,000. How much change did he receive?
Solution:
Step 1: Cost of shirts: 5 × 3,500 = 17,500
Step 2: Cost of trousers: 3 × 5,000 = 15,000
Step 3: Total cost: 17,500 + 15,000 = 32,500
Step 4: Change: 50,000 - 32,500 = 17,500
Answer: ₦17,500 change
Problem: A trader bought 120 bags of rice at ₦15,000 each. He sold them at ₦18,000 each. What was his total profit?
Solution:
Step 1: Total cost: 120 × 15,000 = 1,800,000
Step 2: Total selling price: 120 × 18,000 = 2,160,000
Step 3: Profit: 2,160,000 - 1,800,000 = 360,000
Answer: ₦360,000 profit
Problem: The scores of 5 students in a test are 85, 92, 78, 88, and 95. What is the average score?
Solution:
Step 1: Sum of scores: 85 + 92 = 177; 177 + 78 = 255; 255 + 88 = 343; 343 + 95 = 438
Step 2: Average: 438 ÷ 5 = 87.6
Answer: The average score is 87.6
Problem: A rectangular garden is 25 m long and 12 m wide. Grass costs ₦500 per square metre. What is the total cost to cover the garden with grass?
Solution:
Step 1: Area = length × width = 25 × 12 = 300 square metres
Step 2: Total cost = 300 × 500 = 150,000
Answer: ₦150,000
Problem: A school has 450 students. They want to arrange them in rows of 24. How many full rows will there be? How many students will be left?
Solution:
Step 1: 450 ÷ 24 = 18 remainder 18 (since 18 × 24 = 432, 450 - 432 = 18)
Answer: 18 full rows, 18 students left.
When solving mixed operation problems, follow the order of operations (multiplication and division before addition and subtraction) unless the problem's steps require a different order.
Practice for Mixed Operations Problems
- A shop sells pencils at ₦200 each and erasers at ₦150 each. If a customer buys 8 pencils and 6 erasers, how much does he pay?
- A farmer has 24 cows. Each cow produces 15 litres of milk per day. He sells the milk at ₦800 per litre. How much money does he earn in 7 days?
- The test scores are 78, 85, 92, 67, 88, and 94. Find the average.
- A rectangular field is 45 m long and 30 m wide. Fencing costs ₦1,200 per metre. What is the total cost to fence the field?
- A school has 500 students. They are arranged in rows of 32. How many full rows? How many students left?
Methods & Techniques
Mastering multi-step word problems requires practice and effective strategies. Use these techniques to improve.
1. Use estimation: Round numbers and estimate the final answer before calculating exactly.
2. Work backwards: Start from your answer and reverse the operations to see if you get back to the given numbers.
3. Check each step: Verify each intermediate calculation before moving to the next step.
4. Does it make sense? Consider whether your answer is reasonable in the context of the problem.
Problem: 5 shirts at ₦3,500 each + 3 trousers at ₦5,000 each. Estimate total.
Estimate:
Shirts: 5 × 3,500 ≈ 5 × 4,000 = 20,000
Trousers: 3 × 5,000 = 15,000
Estimate total: 20,000 + 15,000 = 35,000
Exact total: 17,500 + 15,000 = 32,500 (close to 35,000) ✓
• Pitfall 1: Missing a step → Solution: List all steps before calculating.
• Pitfall 2: Using the wrong operation → Solution: Identify clue words (total = add, difference = subtract, each = multiply, share = divide).
• Pitfall 3: Forgetting units → Solution: Always write units in your answer.
• Pitfall 4: Rushing → Solution: Read the problem twice and plan before solving.
• Pitfall 5: Not checking answer → Solution: Always estimate or work backwards to verify.
| Addition | Subtraction | Multiplication | Division |
|---|---|---|---|
| Total, sum, altogether, in all, combined | Difference, less, fewer, remaining, left, how many more | Product, times, each, per, of, twice, triple | Quotient, share, split, divide, average, each |
Technique Practice
- Estimate the answer for: 48 × 19 + 234.
- Work backwards: If the answer is 50 and you added 20 and multiplied by 2, what was the original number?
- Identify the correct operation for: "How many more" and "altogether".
- A student solved 5 × 12 + 8 = 100. Is this correct? If not, what is the correct answer?
Real-World Applications
Multi-step word problems appear in many real-life situations. Understanding how to solve them helps in budgeting, shopping, cooking, planning events, and many other daily activities.
Scenario: A family's monthly income is ₦250,000. They spend ₦80,000 on rent, ₦50,000 on food, ₦20,000 on transport, and ₦15,000 on utilities. They want to save the rest. How much can they save?
Problem: Find total expenses, then subtract from income.
Solution:
Total expenses = 80,000 + 50,000 + 20,000 + 15,000 = 165,000
Savings = 250,000 - 165,000 = 85,000
Answer: They can save ₦85,000.
Scenario: A party planner needs to buy 120 plates. Plates come in packs of 24. How many packs should she buy?
Problem: Divide total needed by pack size.
Solution:
120 ÷ 24 = 5 packs exactly
Answer: 5 packs
Scenario: A recipe for 8 people requires 4 cups of flour. How many cups are needed for 20 people?
Problem: Find cups per person, then multiply.
Solution:
Cups per person = 4 ÷ 8 = 0.5 cups
For 20 people = 0.5 × 20 = 10 cups
Answer: 10 cups
Scenario: A bus travels 240 km in 3 hours. At the same speed, how far will it travel in 5 hours?
Problem: Find speed, then multiply by time.
Solution:
Speed = 240 ÷ 3 = 80 km/h
Distance in 5 hours = 80 × 5 = 400 km
Answer: 400 km
Scenario: A ₦25,000 jacket is on sale at 20% off. How much does it cost after discount?
Problem: Find discount amount, then subtract.
Solution:
Discount = 20% of 25,000 = 0.20 × 25,000 = 5,000
Sale price = 25,000 - 5,000 = 20,000
Answer: ₦20,000
Cross-Curricular Connections
- Science: Calculating averages, rates, and measurements
- Economics: Budgeting, profit and loss, discounts
- Cooking: Scaling recipes, measuring ingredients
- Travel: Distance, time, speed calculations
- Sports: Averages, totals, differences in scores
Cumulative Practice Exercises
Try these problems on your own. Show all working steps. Use estimation to check your answers.
- A shop sold 245 bags of rice on Monday, 312 on Tuesday, and 278 on Wednesday. How many bags were sold in three days?
- A woman had ₦75,000. She bought a dress for ₦12,500, shoes for ₦8,750, and a bag for ₦15,000. How much money is left?
- A factory produces 345 bottles per hour. How many bottles in 12 hours?
- A school has 24 classes with 32 students in each class. If 48 students are absent, how many are present?
- A car travels 420 km on 35 litres of fuel. How far on 25 litres?
- A trader bought 80 bags of cement at ₦4,500 each. He sold them at ₦5,200 each. What was his total profit?
- The scores of 6 students are 75, 82, 90, 68, 85, and 92. Find the average.
- A rectangular garden is 35 m long and 20 m wide. Fencing costs ₦800 per metre. Find the total cost to fence the garden.
- A school has 520 students. They are arranged in rows of 28. How many full rows? How many students left?
- A ₦45,000 television is on sale at 15% off. What is the sale price?
- A recipe for 6 people needs 3 cups of flour. How many cups for 15 people?
- A bus travels 300 km in 4 hours. At the same speed, how far in 7 hours?
- A shop sells pencils at ₦150 each and rulers at ₦250 each. A customer buys 10 pencils and 5 rulers. How much does he pay?
- Error analysis: A student solved 12 × 8 + 6 = 102. Is this correct? If not, correct it.
- A farmer has 36 cows. Each cow produces 12 litres of milk per day. He sells milk at ₦600 per litre. How much money does he earn in 5 days?
Answers to Cumulative Exercises
- Problem: 245 + 312 + 278.
Answer: 835 bags - Problem: 75,000 - (12,500 + 8,750 + 15,000).
Answer: 75,000 - 36,250 = ₦38,750 - Problem: 345 × 12.
Answer: 4,140 bottles - Problem: (24 × 32) - 48.
Answer: 768 - 48 = 720 students - Problem: (420 ÷ 35) × 25.
Answer: 12 × 25 = 300 km - Problem: 80 × (5,200 - 4,500).
Answer: 80 × 700 = ₦56,000 profit - Problem: (75 + 82 + 90 + 68 + 85 + 92) ÷ 6.
Answer: 492 ÷ 6 = 82 - Problem: Perimeter = 2 × (35 + 20) = 110 m; Cost = 110 × 800 = ₦88,000
- Problem: 520 ÷ 28 = 18 remainder 16.
Answer: 18 full rows, 16 students left - Problem: Discount = 0.15 × 45,000 = 6,750; Sale price = 45,000 - 6,750 = ₦38,250
- Problem: (3 ÷ 6) × 15 = 0.5 × 15 = 7.5 cups
- Problem: Speed = 300 ÷ 4 = 75 km/h; Distance = 75 × 7 = 525 km
- Problem: (10 × 150) + (5 × 250) = 1,500 + 1,250 = ₦2,750
- Problem: 12 × 8 + 6 = 96 + 6 = 102, not 100. The student was actually correct! 12 × 8 = 96, + 6 = 102 ✓
- Problem: 36 × 12 × 5 × 600 = 36 × 12 = 432 litres per day; 432 × 5 = 2,160 litres in 5 days; 2,160 × 600 = ₦1,296,000
Conclusion & Summary
Multi-step word problems help us solve real-life situations that require several mathematical operations. By following a systematic approach — reading carefully, planning steps, solving one at a time, and checking your answer — you can solve even the most complex problems.
Key Takeaways:
1. Read carefully: Understand what the problem is asking.
2. Plan steps: Identify hidden questions and decide the order of operations.
3. Solve step by step: Perform one calculation at a time and write intermediate answers.
4. Check your work: Use estimation or work backwards to verify.
5. Practice regularly: The more you practice, the better you become at identifying the steps.
6. Real-world use: Budgeting, shopping, cooking, travel, and many other daily activities.
Keep practising with different types of problems. Multi-step problem solving is a valuable life skill!
Video Resource
Watch this video for more examples of solving multi-step word problems.
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