Word Problems on Addition and Subtraction

Word problems are an essential part of math education, helping students develop critical thinking and problem-solving skills. In this lesson, we will focus on word problems involving addition and subtraction, which form the basis for more complex arithmetic operations. In Class 4, students are expected to solve word problems by translating text into mathematical expressions.

Understanding word problems

Word problems are mathematical problems presented in the form of a story or a real-life scenario. To solve them, students need to follow these steps:

1. Read the question carefully and understand what is being asked.
2. Identify the key information and numbers given in the problem.
3. Decide whether you want to add or subtract.
4. Write mathematical equations using addition or subtraction.
5. Solve the equation to know the answer.

Example 1: Simple addition word problem

Let's look at a simple word problem:

Anna has 12 apples. She buys 5 more apples. How many apples does Anna have now?

To solve this problem we can use summation:

    12 (apples Anna has) + 5 (apples she buys) = 17 apples

Example 2: Simple subtraction word problem

Now, consider a subtraction problem:

John has 20 candies. He gives 8 candies to his friend. How many candies does John have left?

In this case, we need to use subtraction:

    20 (candies John has) - 8 (candies he gives) = 12 candies

Strategies for solving word problems

When solving word problems, students can use different strategies to make the process easier:

• Picture it: Visualizing the problem can help you understand the situation better.
• Look for patterns: Identify patterns or repeated information in the problem.
• Break the problem down into smaller parts: Simplify the problem by tackling one part at a time.
• Use logical reasoning: Think about the possible outcomes and see how they relate to the information given.

Use of addition and subtraction together

Sometimes a problem may require both addition and subtraction. Here's an example:

Sarah had 15 balloons. She got 6 more balloons, but 4 of them burst. How many balloons does she have now?

To solve this, we proceed step by step:

1. Add the balloons that Sarah received:

               15 + 6 = 21
           

2. Reduce the number of balloons that pop:

               21 - 4 = 17
           

Sarah now has 17 balloons.

Practice problems

Here are some additional practice problems to hone your skills:

Problem 1

Michael had 30 marbles. He won 15 new marbles in a game and later gave 10 marbles to his friend. How many marbles does he have now?

Solution:

1. Add up the marbles you've won:

               30 + 15 = 45
           

2. Subtract the given marbles:

               45 - 10 = 35
           

Michael now has 35 marbles.

Problem 2

Pamela read 20 pages of a book on Monday. On Tuesday she read 25 more pages, but on Wednesday she decided to read 10 pages from the previous day again. How many new pages had she read by the end of Wednesday?

Solution:

1. Add new pages read on Tuesday:

               20 + 25 = 45
           

2. Decrease reread pages:

               45 - 10 = 35
           

Pamela had read 35 new pages by the end of Wednesday.

Problem 3

A farmer has 50 cows. 8 new calves were born over the weekend, but 3 cows were sold to a neighboring farmer. How many cows does the farmer have now?

Solution:

1. Add new calves:

               50 + 8 = 58
           

2. Subtract the number of cows sold:

               58 - 3 = 55
           

The farmer now has 55 cows.

Conclusion

Word problems can often seem challenging at first, but with practice, they become easier to handle. By reading each problem carefully, identifying important information, and using basic arithmetic operations such as addition and subtraction, students can solve a variety of real-world problems. The skills developed through solving such problems are not only essential for mathematical proficiency but are also beneficial in everyday decision-making and critical thinking.

Additional tips for solving word problems

• Highlight or underline key information as you read the problem.
• Write down what you know and what you need to find out.
• Verify your answer by double-checking your math and making sure it makes sense in the context of the problem.
• Practice regularly to solve word problems faster and gain more confidence.

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