Weight Basic 3 Mathematics Lesson Note

A. COUNTING SKILL: NUMBERS 921-940

Counting from 921 to 940: 921, 922, 923, 924, 925, 926, 927, 928, 929, 930, 931, 932, 933, 934, 935, 936, 937, 938, 939, 940

Practice counting:

• From 925 to 935: _______
• From 932 to 940: _______
• Backwards from 940 to 930: _______

Fill in missing numbers:

• 926, 927, _____, 929, _____
• 935, _____, 937, _____, 939
• _____, 922, _____, 924, _____

B. WRITING SKILL: WRITING OF THE NUMBERS

Write in words:

• 921 = Nine hundred and twenty-one
• 925 = Nine hundred and twenty-five
• 930 = Nine hundred and thirty
• 935 = Nine hundred and thirty-five
• 940 = Nine hundred and forty

Write in figures:

• Nine hundred and twenty-three = _______
• Nine hundred and twenty-eight = _______
• Nine hundred and thirty-two = _______
• Nine hundred and thirty-seven = _______
• Nine hundred and thirty-nine = _______

C. UNITS OF WEIGHT MEASUREMENT

What is weight? Weight tells us how heavy something is.

Units of weight:

• Gram (g) – for light objects
• Kilogram (kg) – for heavy objects

Relationship: 1 kilogram (kg) = 1000 grams (g)

Examples of light objects (measured in grams):

• A pencil = about 10g
• A coin = about 5g
• A slice of bread = about 25g
• An apple = about 150g
• A book = about 300g

Examples of heavy objects (measured in kilograms):

• A bag of rice = 5kg
• A pupil = about 25kg
• A teacher = about 60kg
• A car = about 1000kg

Converting between grams and kilograms:

• 1kg = 1000g
• 2kg = 2000g
• 3kg = 3000g
• 500g = 0.5kg (half kilogram)

Practice conversions:

1. 4kg = _____ g
2. 6kg = _____ g
3. 2000g = _____ kg
4. 5000g = _____ kg
5. 1500g = _____ kg

Choose the right unit (g or kg):

1. Weight of a feather: 2___
2. Weight of a bag of flour: 10___
3. Weight of a baby: 4___
4. Weight of a paper clip: 1___
5. Weight of a bicycle: 15___

D. CALCULATING WEIGHT OF OBJECTS

Adding weights:

• 2kg + 3kg = 5kg
• 500g + 300g = 800g
• 1kg + 2000g = 1kg + 2kg = 3kg

Subtracting weights:

• 5kg – 2kg = 3kg
• 800g – 250g = 550g
• 3kg – 1500g = 3000g – 1500g = 1500g = 1.5kg

Practice adding weights:

1. 3kg + 4kg = _____ kg
2. 200g + 150g = _____ g
3. 2kg + 1kg = _____ kg
4. 400g + 300g = _____ g
5. 1kg + 500g = _____ g

Practice subtracting weights:

1. 8kg – 3kg = _____ kg
2. 500g – 200g = _____ g
3. 10kg – 4kg = _____ kg
4. 800g – 350g = _____ g
5. 2kg – 500g = _____ g

Comparing weights: Which is heavier?

1. 2kg or 1500g? _____
2. 800g or 1kg? _____
3. 3000g or 2kg? _____
4. 500g or 1kg? _____

E. CALCULATING WEIGHT OF SOME OBJECTS

Weighing common objects:

Kitchen items:

• 1 cup of rice = 200g
• 1 cup of flour = 150g
• 1 egg = 60g
• 1 tomato = 100g

School items:

• 1 exercise book = 50g
• 1 textbook = 250g
• 1 pencil case = 100g
• School bag (empty) = 500g

Calculate total weights:

Example 1: Weight of lunch

• 2 slices of bread = 2 × 25g = 50g
• 1 apple = 150g
• Total = 50g + 150g = 200g

Example 2: Weight in school bag

• 3 textbooks = 3 × 250g = 750g
• 2 exercise books = 2 × 50g = 100g
• 1 pencil case = 100g
• Total = 750g + 100g + 100g = 950g

Practice calculations:

1. Weight of 4 apples (each 150g): _____ g
2. Weight of 2 bags of rice (each 5kg): _____ kg
3. Total weight: 3 eggs + 2 tomatoes = (3 × 60g) + (2 × 100g) = _____ g
4. A box weighs 200g. It contains 5 books of 250g each. Total weight = 200g + (5 × 250g) = _____ g

F. QUANTITATIVE REASONING

Word problems:

1. Kemi weighs 30kg. Her baby brother weighs 8kg. What is their total weight?
2. A bag of sugar weighs 2kg. Tolu uses 500g for cooking. How much sugar is left?
3. Ada buys 3 packets of biscuits. Each packet weighs 200g. What is the total weight?
4. A crate of oranges weighs 15kg. The empty crate weighs 2kg. What is the weight of just the oranges?

Estimation problems:

1. About how much would 10 pencils weigh? _____
2. About how much would 5 apples weigh? _____
3. Which is closer to 1kg: 10 books or 100 coins? _____

Comparison problems:

1. Who is heavier: a pupil weighing 25kg or a teacher weighing 60kg?
2. What weighs more: 5 textbooks or 1 bag of rice?
3. Which package is lighter: 800g or 1.2kg?

Real-life applications:

1. A trader sells fruits. She has:
   1. 20 apples (150g each)
   2. 10 oranges (200g each) What is the total weight of fruits?
2. Bola’s luggage must not exceed 20kg. She packs:
   1. Clothes: 8kg
   2. Books: 5kg
   3. Shoes: 3kg
   4. Gifts: 6kg Is her luggage too heavy?

Pattern recognition:

1. 1kg, 2kg, 3kg, _____, _____
2. 100g, 200g, 300g, _____, _____
3. 500g, 1kg, 1500g, _____, _____

CLASS EXERCISES

1. Count from 928 to 938:
2. Write in words:
   1. 927 = _______
   2. 933 = _______
   3. 940 = _______
3. Convert weights:
   1. 7kg = _____ g
   2. 3000g = _____ kg
   3. 8kg = _____ g
   4. 4500g = _____ kg
4. Choose the right unit (g or kg):
   1. Weight of a car: 800___
   2. Weight of a banana: 120___
   3. Weight of a person: 50___
   4. Weight of a coin: 5___
5. Add weights:
   1. 4kg + 3kg = _____ kg
   2. 300g + 200g = _____ g
   3. 2kg + 1500g = _____ g
6. Subtract weights:
   1. 9kg – 4kg = _____ kg
   2. 700g – 250g = _____ g
   3. 3kg – 800g = _____ g
7. Compare weights:
   1. Which is heavier: 1500g or 2kg? _____
   2. Which is lighter: 900g or 1kg? _____
8. Calculate total weights:
   1. 6 books, each weighing 300g: _____ g
   2. 3 bags of flour, each 2kg: _____ kg
9. Word problems:
   1. Emeka weighs 28kg. His sister weighs 15kg. What is their combined weight?
   2. A trader buys 5kg of tomatoes and uses 2kg. How much is left?
10. Problem solving: A school bag weighs 800g when empty. A pupil puts in 4 textbooks (250g each) and 3 exercise books (50g each). What is the total weight of the bag with books?