Mathematics - Term 1 - Week 10

Problem solving in mathematics involves identifying a problem, devising a plan, carrying out the plan, and reviewing the solution. This week, we will focus on breaking down problems into manageable steps. We will use visual models, such as number lines and bar models, to represent problems visually, making it easier to understand and solve them.

Consider the problem: 'Sarah has 12 apples. She gives 4 apples to her friend. How many apples does she have left?' To solve this, we can represent the problem using a number line. Start at 12, and move 4 spaces to the left. This shows that Sarah has 8 apples remaining. We can also write the equation: 12 - 4 = 8. This method helps us visualize the subtraction process.

Let's solve another problem together: 'There are 20 students in a class. If 5 students are absent, how many students are present?' First, we identify the total number of students (20) and the number absent (5). We can use subtraction to find the number present: 20 - 5 = 15. Now, let's draw a bar model to represent this situation. The bar will show 20 students, with a section removed to indicate the 5 absent students, leaving us with 15 present students.

Now it's your turn! Solve the following problems independently. Remember to show your working clearly. 1. A baker has 30 cookies. He sells 12. How many cookies does he have left? 2. There are 15 birds on a tree. If 7 fly away, how many are left? 3. A library has 50 books. If 10 are checked out, how many books remain? Use visual models if it helps you.

• Review the solution
• Identify the problem
• Carry out the plan
• Write the answer

Answer: Identify the problem

The first step in problem solving is to clearly identify what the problem is before attempting to solve it.

• 7 apples
• 6 apples
• 8 apples
• 5 apples

Answer: 7 apples

You subtract the 3 apples given away from the 10 apples you originally had: 10 - 3 = 7.

Answer: I would subtract the number of girls from the total number of students: 25 - 10 = 15 boys.

This shows the process of subtraction to find the number of boys in the class.

• Bar model
• Pie chart
• Line graph
• Venn diagram

Answer: Bar model

A bar model visually represents quantities and can effectively illustrate the process of subtraction.

Answer: 11

Subtracting 7 from 18 gives us 11.

• Addition
• Subtraction
• Multiplication
• Division

Answer: Subtraction

You would use subtraction to find out how many marbles John has left after losing some.

• Ignore the answer
• Review your solution
• Ask someone else
• Write it down

Answer: Review your solution

Reviewing your solution helps ensure that your answer is correct and that you understand the process.