# Addition, Subtraction, Multiplication and Division of Weight Measurements Primary 4 Third Term Lesson Notes  Mathematics Week 3

### Subject : Mathematics

Class :Primary 4

Term :Third Term

Week :Week 3

Topic :

Addition, Subtraction, Multiplication and Division of Weight Measurements Primary 4 Third Term Lesson Notes  Mathematics Week 3

Previous Lesson :

Estimating length and comparing measurements Primary 4 Third Term Lesson Notes  Mathematics Week 2

### Learning Objectives:

1. Understand the concepts of addition and subtraction of weight.
2. Perform addition and subtraction of weight in kilograms and grams accurately.
3. Understand the concepts of multiplication and division of weight.
4. Perform multiplication and division of weight in kilograms and grams by whole numbers correctly.

### Embedded Core Skills:

1. Numerical computation
2. Problem-solving
3. Measurement and conversion
4. Logical reasoning
5. Critical thinking

### Learning Materials:

1. Whiteboard and markers
2. Worksheets with weight-related problems
3. Weights (such as kilogram weights and gram weights)
4. Real-life objects with known weights (optional)
5. Calculators (optional)

First Lesson

### Addition and Subtraction of Weight

Good morning, class! Today, we are going to learn about a very important topic in mathematics: addition and subtraction of weight.

Weight is a measure of how heavy something is. We often use different units to measure weight, such as kilograms (kg) and grams (g). When we add or subtract weights, we need to make sure that we are using the same unit for all the numbers.

Let’s start with addition. When we add weights, we simply combine them to find the total weight. For example, if we have a bag of apples that weighs 2 kilograms (kg) and another bag that weighs 3 kilograms (kg), we can find the total weight by adding 2 kg + 3 kg. This gives us a total weight of 5 kilograms (kg).

Now, let’s move on to subtraction. When we subtract weights, we take away one weight from another to find the difference. For example, if we have a box of books that weighs 7 kilograms (kg) and we remove 4 kilograms (kg) of books from it, we can find the remaining weight by subtracting 4 kg from 7 kg. This gives us a remaining weight of 3 kilograms (kg).

Remember, it’s important to use the same unit when adding or subtracting weights. If we have weights in grams (g), we need to convert them to the same unit before performing the operation.

Now, let’s practice a few examples together:

Example 1:
Sarah has a bag of sugar that weighs 2 kilograms (kg) and another bag that weighs 500 grams (g). How much is the total weight?

To solve this, we need to convert grams (g) to kilograms (kg) because we want to use the same unit. There are 1000 grams in 1 kilogram, so 500 grams is equal to 500/1000 = 0.5 kilograms (kg). Now, we can add the weights: 2 kg + 0.5 kg = 2.5 kilograms (kg). Therefore, the total weight is 2.5 kilograms (kg).

Example 2:
Michael has a box of toys that weighs 1 kilogram (kg) and he removes 300 grams (g) of toys from it. What is the remaining weight?

Again, we need to convert grams (g) to kilograms (kg) before subtracting. 300 grams is equal to 300/1000 = 0.3 kilograms (kg). Now, we can subtract the weights: 1 kg – 0.3 kg = 0.7 kilograms (kg). Therefore, the remaining weight is 0.7 kilograms (kg).

I hope that helps you understand how to add and subtract weights, class. Remember to always use the same unit and convert if necessary. Keep practicing, and soon you’ll become experts in addition and subtraction of weight. Good luck!

### Evaluation

1. The weight of a pencil is 20 grams (g) and the weight of an eraser is 15 grams (g). The total weight of the pencil and eraser is ______ grams (g). a) 5 g b) 35 g c) 45 g
2. A bag of flour weighs 2 kilograms (kg) and a bag of sugar weighs 500 grams (g). The total weight is ______ kilograms (kg) and ______ grams (g). a) 2 kg, 500 g b) 3 kg, 500 g c) 2 kg, 5 g
3. A book weighs 750 grams (g) and a notebook weighs 150 grams (g). The total weight is ______ grams (g). a) 900 g b) 600 g c) 300 g
4. Tim has a box that weighs 2.5 kilograms (kg). He removes 1 kilogram (kg) of toys from the box. The remaining weight is ______ kilograms (kg). a) 1.5 kg b) 3.5 kg c) 1 kg
5. A watermelon weighs 3 kilograms (kg) and an apple weighs 200 grams (g). The total weight is ______ kilograms (kg) and ______ grams (g). a) 3 kg, 2 g b) 3 kg, 200 g c) 4 kg, 200 g
6. Alex has a bag that weighs 350 grams (g). He adds 150 grams (g) of candies to the bag. The total weight is ______ grams (g). a) 500 g b) 200 g c) 250 g
7. The weight of a pencil is 10 grams (g) and the weight of a pen is 5 grams (g). The difference in weight between the pencil and pen is ______ grams (g). a) 15 g b) 5 g c) 3 g
8. A box of chocolates weighs 800 grams (g) and some chocolates are taken out, which weigh 250 grams (g) in total. The remaining weight of the box is ______ grams (g). a) 550 g b) 1,050 g c) 650 g
9. A bag of rice weighs 5 kilograms (kg) and a bag of beans weighs 3 kilograms (kg). The total weight is ______ kilograms (kg). a) 2 kg b) 8 kg c) 15 kg
10. Lisa has a box that weighs 1.2 kilograms (kg). She adds 800 grams (g) of books to the box. The total weight is ______ kilograms (kg) and ______ grams (g). a) 2 kg, 800 g b) 2 kg, 1,000 g c) 1 kg, 800 g
11. The weight of a pencil is 5 grams (g) and the weight of a ruler is 100 grams (g). The total weight is ______ grams (g). a) 50 g b) 10 g c) 105 g
12. A bag of marbles weighs 250 grams (g) and a bag of stones weighs 1 kilogram (kg). The total weight is ______ kilograms (kg) and ______ grams a) 1 kg, 250 g b) 1 kg, 500 g c) 2 kg, 250g
13. Tom has a box that weighs 3.5 kilograms (kg). He removes 2.2 kilograms (kg) of clothes from the box. The remaining weight is ______ kilograms (kg). a) 1.3 kg b) 5.7 kg c) 3.2 kg
14. A bag of chips weighs 150 grams (g) and a bag of cookies weighs 300 grams (g). The total weight is ______ grams (g). a) 450 g b) 200 g c) 600 g
15. Jane has a box that weighs 4.5 kilograms (kg). She adds 800 grams (g) of toys to the box. The total weight is ______ kilograms (kg) and ______ grams (g). a) 5 kg, 300 g b) 4 kg, 1,300 g c) 4.5 kg, 800 g
16. The weight of a water bottle is 250 grams (g) and the weight of a juice box is 200 grams (g). The difference in weight between the water bottle and juice box is ______ grams (g). a) 450 g b) 50 g c) 500 g
17. A bag of apples weighs 1.2 kilograms (kg) and a bag of oranges weighs 800 grams (g). The total weight is ______ kilograms (kg) and ______ grams (g). a) 1 kg, 200 g b) 2 kg, 800 g c) 2.4 kg, 80 g
18. Mike has a bag that weighs 600 grams (g). He adds 300 grams (g) of candies to the bag. The total weight is ______ grams (g). a) 900 g b) 200 g c) 250 g
19. The weight of a book is 400 grams (g) and the weight of a notebook is 200 grams (g). The difference in weight between the book and notebook is ______ grams (g). a) 600 g b) 200 g c) 100 g
20. A box of chocolates weighs 1 kilogram (kg) and some chocolates are taken out, which weigh 400 grams (g) in total. The remaining weight of the box is ______ grams (g).

Packaging and labeling: the importance of accurate weight measurement

Second Lesson

### Multiplication and Division of Weight

Good morning, class! Today, we are going to dive into another important topic in mathematics: multiplication and division of weight in kilograms and grams by whole numbers.

When we multiply weight, we are essentially finding the result of repeated addition. For example, if we have a bag of apples that weighs 2 kilograms (kg) and we want to find the total weight of 4 bags, we can multiply 2 kg by 4. This gives us 2 kg × 4 = 8 kg. So, the total weight of 4 bags of apples is 8 kilograms (kg).

Now, let’s move on to division. Division is the opposite of multiplication. It involves separating a quantity into equal parts. For example, if we have 6 kilograms (kg) of sugar and we want to divide it equally into 2 bags, we can divide 6 kg by 2. This gives us 6 kg ÷ 2 = 3 kg. So, each bag will have 3 kilograms (kg) of sugar.

When working with weights in kilograms and grams, it’s important to pay attention to the units. We need to make sure that the units are consistent throughout the calculations. For example, if we have a weight of 1.5 kilograms (kg) and we want to multiply it by 3, we need to multiply both the whole number and the decimal part separately.

Let’s practice a few examples together:

Example 1:
A box of chocolates weighs 500 grams (g). How much would 3 boxes weigh?

To find the total weight of 3 boxes, we need to multiply the weight of one box by 3: 500 g × 3 = 1500 grams (g). So, 3 boxes would weigh 1500 grams (g).

Example 2:
A bag of rice weighs 2 kilograms (kg). If we want to divide it into 4 equal parts, how much would each part weigh?

To find the weight of each part, we need to divide the total weight by the number of parts: 2 kg ÷ 4 = 0.5 kilograms (kg). So, each part would weigh 0.5 kilograms (kg).

Remember to keep track of the units and pay attention to the whole numbers and decimal parts when multiplying or dividing weights in kilograms and grams.

Now, it’s time for you to practice some multiplication and division of weight problems on your own. I will give you a set of questions to work on, and you can solve them using the concepts we discussed. Don’t forget to show your work and double-check your answers.

Feel free to ask me any questions if you need further clarification. Happy calculating!

### Evaluation

1. A bag of flour weighs 1.5 kilograms (kg). If we have 4 bags, the total weight would be ______ kilograms (kg). a) 4.5 kg b) 5.5 kg c) 6.5 kg
2. A box of pencils weighs 250 grams (g). If we have 6 boxes, the total weight would be ______ grams (g). a) 1,000 g b) 1,500 g c) 1,750 g
3. Sarah has 3 kilograms (kg) of apples. If she divides them equally into 4 bags, each bag would weigh ______ kilograms (kg). a) 0.5 kg b) 0.75 kg c) 1.25 kg
4. A watermelon weighs 2.8 kilograms (kg). If we want to divide it into 5 equal parts, each part would weigh ______ kilograms (kg). a) 0.4 kg b) 0.56 kg c) 0.35 kg
5. Tom has 500 grams (g) of candy. If he wants to multiply the weight by 2, the total weight would be ______ grams (g). a) 1,000 g b) 1,500 g c) 2,000 g
6. The weight of a book is 450 grams (g). If we have 3 identical books, the total weight would be ______ grams (g). a) 1,350 g b) 1,050 g c) 1,400 g
7. A bag of rice weighs 1 kilogram (kg) and 500 grams (g). If we multiply the weight by 6, the total weight would be ______ kilograms (kg) and ______ grams (g). a) 6 kg, 3 g b) 7 kg, 500 g c) 9 kg, 3 g
8. Lisa has 1.2 kilograms (kg) of sugar. If she divides it equally into 3 bags, each bag would weigh ______ kilograms (kg). a) 0.2 kg b) 0.4 kg c) 0.6 kg
9. A box of chocolates weighs 800 grams (g). If we have 2 boxes, the total weight would be ______ grams (g). a) 1,200 g b) 1,400 g c) 1,600 g
10. The weight of a water bottle is 250 grams (g). If we multiply the weight by 5, the total weight would be ______ grams (g). a) 500 g b) 1,000 g c) 1,250 g
11. John has 2 kilograms (kg) of apples. If he wants to divide them equally into 8 bags, each bag would weigh ______ kilograms (kg). a) 0.25 kg b) 0.4 kg c) 0.16 kg
12. A bag of candies weighs 150 grams (g). If we multiply the weight by 10, the total weight would be ______ grams (g). a) 1,000 g b) 1,500 g c) 1,650 g
13. A box of markers weighs 1.8 kilograms (kg). If we have 5 boxes, the total weight would be ______ kilograms (kg). a) 2.3 kg b) 4.3 kg c) 9 kg
14. Sarah has 600 grams (g) of clay. If she wants to divide it equally into 6 portions, each portion would weigh ______ grams (g). a) 100 g b) 200 g c) 300 g
15. A box of markers weighs 1.8 kilograms (kg). If we have 5 boxes, the total weight would be ______ kilograms (kg). a) 2.3 kg b) 4.3 kg c) 9 kg
16. Sarah has 600 grams (g) of clay. If she wants to divide it equally into 6 portions, each portion would weigh ______ grams (g). a) 100 g b) 200 g c) 300 g
17. Tom has 1.5 kilograms (kg) of sand. If he wants to divide it equally into 6 containers, each container would weigh ______ kilograms (kg). a) 0.25 kg b) 0.4 kg c) 0.6 kg
18. The weight of a bookshelf is 2.5 kilograms (kg). If we multiply the weight by 7, the total weight would be ______ kilograms (kg). a) 15 kg b) 17.5 kg c) 21 kg
19. A bag of toys weighs 800 grams (g). If we have 4 bags, the total weight would be ______ grams (g). a) 2,200 g b) 3,200 g c) 3,600 g
20. Jane has 2.4 kilograms (kg) of flour. If she wants to divide it equally into 8 bags, each bag would weigh ______ kilograms (kg). a) 0.2 kg b) 0.3 kg c) 0.4 kg

Great job, class! Remember to carefully read the questions and choose the best option that completes each statement. These exercises will help reinforce your understanding of multiplication and division of weight in kilograms and grams by whole numbers.

If you have any questions, feel free!

Weight measurement in transportation and logistics

### Lesson Plan Presentation

Topic:

Addition and Subtraction of Weight; Multiplication and Division of Weight in Kilograms and Grams by Whole Numbers

Duration: 60 minutes

Presentation:

1. Introduction (5 minutes) a. Greet the students and briefly recap their previous knowledge about weight and units of measurement. b. Explain that in this lesson, we will focus on addition, subtraction, multiplication, and division of weight in kilograms and grams.
2. Addition and Subtraction of Weight (15 minutes) a. Explain the concept of addition and subtraction of weight using real-life examples. b. Present examples on the whiteboard and demonstrate how to add and subtract weights in kilograms and grams, ensuring the units remain consistent. c. Engage the students in solving practice problems on the whiteboard. d. Provide opportunities for students to practice addition and subtraction of weight in pairs or individually, using worksheets or real-life objects with known weights. e. Monitor and assist students during their practice.
3. Multiplication and Division of Weight (15 minutes) a. Introduce the concept of multiplication and division of weight in kilograms and grams. b. Show examples on the whiteboard and explain how to multiply and divide weights using whole numbers. c. Demonstrate the conversion between kilograms and grams when necessary. d. Provide practice problems for the students to solve, either individually or in pairs, using worksheets or real-life objects. e. Circulate among the students to provide assistance and guidance as needed.
4. Assessment (10 minutes) a. Conduct a brief assessment to evaluate students’ understanding. b. Ask students to solve weight-related problems individually or in pairs. c. Assess their ability to apply the concepts of addition, subtraction, multiplication, and division of weight accurately.
5. Evaluation Questions (10 minutes) Provide the students with ten evaluation questions related to the topics covered:
1. What is the result of adding 3 kilograms and 500 grams?
2. How would you subtract 750 grams from 2.5 kilograms?
3. If a box weighs 1.2 kilograms, what is the weight of 4 identical boxes?
4. How would you divide 800 grams into 4 equal parts?
5. If a bag of rice weighs 2.5 kilograms, what is the total weight of 6 bags?
6. Multiply 300 grams by 5.
7. Divide 1.5 kilograms into 3 equal parts.
8. What is the weight of 2 boxes, each weighing 1.8 kilograms?
9. How would you add 600 grams and 1.2 kilograms?
10. Divide 900 grams into 6 equal parts.
6. Conclusion (5 minutes) Summarize the key concepts covered in the lesson, emphasizing the importance of accuracy and consistency in units of measurement. Encourage students to practice addition, subtraction, multiplication, and division of weight in their daily lives to reinforce their understanding.
7. Homework Assignment (5 minutes) Assign homework exercises related to addition, subtraction, multiplication, and division of weight. Provide clear instructions and a due date for submission.
8. Recap and Review (5 minutes) Review the main concepts covered in the lesson by asking a few recap questions. Allow students to ask any remaining questions they may have.
9. Closure (2 minutes) Summarize the key points of the lesson once again and emphasize the importance of practicing the skills learned. Encourage students to seek help if they encounter any difficulties.
10. Follow-up Activities (Ongoing) Reinforce the concepts learned through periodic weight-related activities, such as measuring the weight of objects in the classroom or discussing the weights of common items at home.

Assessment (Ongoing): Monitor students’ participation and progress throughout the lesson. Provide feedback during individual and group activities. Evaluate completed worksheets and homework assignments for accuracy and understanding.

Evaluation Questions:

1. What is the result of adding 3 kilograms and 500 grams? a) 3.5 kilograms b) 3.5 grams c) 35 kilograms
2. How would you subtract 750 grams from 2.5 kilograms? a) 1.75 kilograms b) 1.75 grams c) 0.75 kilograms
3. If a box weighs 1.2 kilograms, what is the weight of 4 identical boxes? a) 4.2 kilograms b) 4.8 kilograms c) 4.5 kilograms
4. How would you divide 800 grams into 4 equal parts? a) 400 grams b) 200 grams c) 300 grams
5. If a bag of rice weighs 2.5 kilograms, what is the total weight of 6 bags? a) 15 kilograms b) 16 kilograms c) 14.5 kilograms
6. Multiply 300 grams by 5. a) 1,000 grams b) 1,500 grams c) 1.5 kilograms
7. Divide 1.5 kilograms into 3 equal parts. a) 500 grams b) 0.5 kilograms c) 0.3 kilograms
8. What is the weight of 2 boxes, each weighing 1.8 kilograms? a) 2.8 kilograms b) 3.6 kilograms c) 3.4 kilograms
9. How would you add 600 grams and 1.2 kilograms? a) 1.8 kilograms b) 1.8 grams c) 18 kilograms
10. Divide 900 grams into 6 equal parts. a) 150 grams b) 100 grams c) 200 grams

Conclusion: By the end of this lesson, you have learned how to perform addition and subtraction of weight in kilograms and grams. You also understand how to multiply and divide weight using whole numbers. Remember to be accurate in your calculations and maintain consistency in the units of measurement. Keep practicing these skills, and they will become even more natural to you. Well done!

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