Lesson Planning of Addition and Subtraction of Units of Mass / weight
Subject Mathematics
Grade 4th
Students` Learning Outcomes
- Add and subtract expressions involving similar units.
- Use appropriate units to measure weight of different objects.
- Solve real life problems with application of above two.
Information for Teachers
- Kilograms and grams are used to measure the weight of different objects.
- Kilograms are used to measure heavy objects whereas grams are used for lighter objects.
- Similar units can be added or subtracted only, if units are not similar, we make them similar before addition or subtraction.
- For adding grams into kilograms first we convert kilograms into grams and for this we multiply number of kilograms by 1000.
- During this lesson, the teacher should consult textbook at each level wherein and whenever it is required.
Material / Resources
Writing board, chalk/marker, duster, school bag, scale, pictures of almond, peanut, flour, rice, sugar and salt, textbook
Introduction
- Collect various objects that are easily available, as; toys, school bags, geometry box etc.
- Place the objects on a table along with a set of simple balances.
- Weigh these objects on balance and write on the board. “The geometry is lighter than school bag”.
- Put some more object on the geometry side and tell the students that now weight of both sides look same.
- Ask the students what do you think would be the weight of all toys.
- Take their feedback and tell them that it would be in kilograms
- Tell them that today we will learn about the application of “units of weight”.
Development
Activity 1 Addition of the same units:
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Activity 2
Or
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Activity 3
i) 75 kg, 888 g + 170 kg, 501 g = ____________? ii) 90 kg, 400 g + 11 kg, 905 g = ____________? iii) 178 kg, 388 g – 59 kg, 430 g = ____________? iv) 32 kg, 332 g – 14 kg, 581 g = ____________?
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Sum up / Conclusion
- Finish this lesson by asking different students to repeat the key concepts that we have learnt today, as; 1 kg = 1000 g
- Kilograms are used to measure heavy objects, whereas grams are used for lighter objects
- Similar units can be added or subtracted only, if units are not similar, we make them similar before addition or subtraction.
- We multiply kg by 1000 to convert kg to g and divide g by 1000 to get kg.
- If expressions involve mix units like kg & g both, we write kg below kg and g below the g and then we add or subtract.
Assessment
- Now assign different questions to the students to assess whether they have got your points or not.
- Take weight of your friend and his /her school bag and find difference which one is heavier, as;
- Ali`s weight is 25 kg and 320 g whereas his bag`s weight is 5 kg and 20 g. which one is heavier and how much?
- Subtract 25 kg, 320 g – 5 kg, 20 g = __________?
Follow up
- Fill in the following table with the help of family members and write amounts of items given below used in a month and then add all the quantities: as ;