Learning Objectives
By the end of this lesson, you will be able to:
- Solve one-step word problems involving addition (Objective 17)
- Solve one-step word problems involving subtraction (Objective 17)
- Solve multi-step word problems involving addition and subtraction (Objectives 18-19)
- Identify key words that indicate addition or subtraction (Objective 30)
- Check your answers using inverse operations
SEA Tip
Word problems appear in Section II and III of the SEA Math paper. These are worth 2-4 marks each! (SEA Framework Page 21-22)
5-Step Problem-Solving Method
- Read the problem carefully (twice if needed)
- Identify what you need to find
- Choose the operation (addition or subtraction)
- Solve the problem step-by-step
- Check your answer using inverse operations
Watch: Addition Word Problems
Start by watching this video to learn how to solve addition word problems. Take notes as you watch! 📝
Addition Word Problems – Mathematics Video Lesson
Quick Check
Did you understand the video? Review the notes below before continuing! ✅
One-Step Addition Word Problems
One-step problems require only ONE operation to solve. Look for key words that tell you to ADD!
🔑 Key Words for Addition:
Addition Key Words
- Total – “What is the total?”
- Altogether – “How many altogether?”
- Sum – “Find the sum”
- Combined – “Combined weight”
- In all – “How many in all?”
- More than – “5 more than”
- Increased by – “Increased by 10”
📊 Example 1: One-Step Addition
Problem & Solution
Question: Maria has 345 stickers. Her friend gives her 178 more stickers. How many stickers does Maria have now?
Solution:
- Read: Maria has stickers, gets more stickers
- Identify: Find total number of stickers
- Choose: Addition (key word: “more”)
- Solve: 345 + 178 = 523
- Check: 523 − 178 = 345 ✓
Answer: Maria has 523 stickers.
Watch: Subtraction Word Problems
Now watch this video to learn how to solve subtraction word problems. Pay attention to the key words! 🎯
Subtraction Word Problems – Mathematics Video Lesson
One-Step Subtraction Word Problems
One-step subtraction problems require only ONE operation. Look for key words that tell you to SUBTRACT!
🔑 Key Words for Subtraction:
Subtraction Key Words
- Difference – “What is the difference?”
- Left – “How many are left?”
- Remaining – “How many remaining?”
- Less than – “5 less than”
- Decreased by – “Decreased by 10”
- Change – “How much change?”
- How many more – “How many more needed?”
📊 Example 2: One-Step Subtraction
Problem & Solution
Question: A school has 850 students. 267 students are absent today. How many students are present?
Solution:
- Read: Total students, some absent, find present
- Identify: Find number of students present
- Choose: Subtraction (key word: absent/left)
- Solve: 850 − 267 = 583
- Check: 583 + 267 = 850 ✓
Answer: There are 583 students present.
Multi-Step Word Problems
Multi-step problems require TWO OR MORE operations. Break them down step-by-step!
📊 Example 3: Multi-Step Problem
Two-Step Problem
Question: A bookstore had 1,500 books. They sold 456 books on Monday and 328 books on Tuesday. How many books are left?
Solution:
- Step 1: Find total books sold: 456 + 328 = 784
- Step 2: Subtract from original: 1,500 − 784 = 716
- Check: 716 + 784 = 1,500 ✓
Answer: There are 716 books left.
📊 Example 4: Multi-Step Problem
Three-Step Problem
Question: John saved $250 in January, $175 in February, and $300 in March. He spent $400 on a bike. How much money does he have left?
Solution:
- Step 1: Find total saved: 250 + 175 + 300 = 725
- Step 2: Subtract amount spent: 725 − 400 = 325
- Check: 325 + 400 = 725 ✓
Answer: John has $325 left.
Common Mistake
Don’t rush! Write down each step. Multi-step problems need careful work. Always check your answer!
Lesson Complete!
Great job finishing Lesson 1.6! You’re mastering word problems for the SEA exam! 🎉
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