Weight Basic 6 Mathematics Lesson Note

Units of Weight

Common Units of Weight

• Gram (g) – smallest unit for light objects
• Kilogram (kg) – 1 kg = 1,000 g
• Tonne (t) – 1 t = 1,000 kg

Conversion Table

1 kg = 1,000 g

1 t = 1,000 kg = 1,000,000 g

Examples of Weight

• 1 gram: A paper clip
• 1 kilogram: A bag of sugar
• 1 tonne: A small car

Conversion of Units

Converting Larger to Smaller Units

Multiply when going from larger to smaller units

Examples:

• 3 kg = 3 × 1,000 = 3,000 g
• 2.5 t = 2.5 × 1,000 = 2,500 kg
• 0.75 kg = 0.75 × 1,000 = 750 g

Converting Smaller to Larger Units

Divide when going from smaller to larger units

Examples:

• 5,000 g = 5,000 ÷ 1,000 = 5 kg
• 3,500 kg = 3,500 ÷ 1,000 = 3.5 t
• 1,250 g = 1,250 ÷ 1,000 = 1.25 kg

Exercise A – Unit Conversion

Convert these weights:

1. 4 kg = ______ g
2. 7.5 kg = ______ g
3. 2,800 g = ______ kg
4. 6,000 g = ______ kg
5. 3 t = ______ kg
6. 4,500 kg = ______ t
7. 0.8 kg = ______ g
8. 12,000 g = ______ kg
9. 2.5 t = ______ g
10. 750 g = ______ kg

Addition and Subtraction of Weight

Addition of Weight

Method 1: Convert to same unit, then add Method 2: Add separately, then simplify

Examples:

Example 1: 3 kg 250 g + 2 kg 400 g Method: Add kg and g separately = (3 + 2) kg + (250 + 400) g = 5 kg 650 g

Example 2: 2.5 kg + 1,800 g Method: Convert to same unit = 2,500 g + 1,800 g = 4,300 g = 4.3 kg

Subtraction of Weight

Similar methods as addition

Example: 5 kg 200 g – 2 kg 800 g Since 200 g < 800 g, borrow 1 kg = 1,000 g = 4 kg 1,200 g – 2 kg 800 g = 2 kg 400 g

Exercise B – Addition and Subtraction

Solve these problems:

1. 3 kg 450 g + 2 kg 350 g = ______
2. 6 kg 200 g + 1 kg 900 g = ______
3. 8 kg 500 g – 3 kg 200 g = ______
4. 7 kg 100 g – 2 kg 800 g = ______
5. 2.5 kg + 1,750 g = ______ (in kg)
6. 4,200 g + 1.8 kg = ______ g
7. 5.7 kg – 2,400 g = ______ g
8. 3 kg 800 g + 4 kg 700 g = ______

Multiplication and Division of Weight

Multiplying Weight

Method: Multiply the number, keep the unit

Examples:

• 3 kg × 4 = 12 kg
• 2.5 kg × 6 = 15 kg
• 450 g × 3 = 1,350 g = 1.35 kg

Dividing Weight

Method: Divide the number, keep the unit

Examples:

• 12 kg ÷ 4 = 3 kg
• 2,400 g ÷ 6 = 400 g
• 7.5 kg ÷ 3 = 2.5 kg

Word Problems with Multiplication and Division

Example: 8 bags of rice each weighing 5 kg. Total weight? Total = 8 × 5 kg = 40 kg

Example: 15 kg of sugar shared equally among 5 families. Weight per family? Weight per family = 15 kg ÷ 5 = 3 kg

Exercise C – Multiplication and Division

Solve these problems:

1. 6 kg × 7 = ______
2. 450 g × 8 = ______ g
3. 18 kg ÷ 6 = ______
4. 2,400 g ÷ 8 = ______ g
5. 12 bags of flour, each 2.5 kg. Total weight = ______
6. 24 kg of beans shared among 8 people. Each gets = ______
7. 5 boxes, each weighing 3 kg 200 g. Total = ______
8. 21 kg ÷ 7 = ______

Exercise D – Mixed Operations

Solve step by step:

1. (4 kg × 3) + (2 kg × 5) = ______
2. (15 kg ÷ 3) – (8 kg ÷ 4) = ______
3. 6 people each carry 2.5 kg. Total carried = ______
4. 20 kg rice is packed in 5 kg bags. Number of bags = ______
5. 3 kg 500 g × 4 = ______

Real Life Problems with Weight

Exercise E – Market and Shopping

Solve these market problems:

1. Fruit Shopping: Mama bought 2 kg 500 g of oranges, 1 kg 800 g of bananas, and 3 kg 200 g of mangoes. What is the total weight? Answer: ______
2. Rice Purchase: A bag of rice weighs 50 kg. If a family uses 1.5 kg daily, how many days will the bag last? Answer: ______ days
3. Meat Distribution: A butcher has 15 kg of meat. He sells it in portions of 750 g each. How many portions can he make? Answer: ______ portions
4. Vegetable Market: Tomatoes cost ₦400 per kg. If Kemi buys 2.5 kg, how much does she pay? Answer: ₦______

Exercise F – School and Classroom

Apply weight to school situations:

1. School Bags: 25 students each carry a bag weighing 3 kg 400 g. What is the total weight of all bags? Answer: ______
2. Books Distribution: 240 textbooks weigh 120 kg in total. What is the weight of each book? Answer: ______ g
3. Sports Equipment: A box contains 12 footballs, each weighing 450 g. What is the total weight of the footballs? Answer: ______ kg
4. School Lunch: If 200 students each eat 300 g of food daily, how much food is needed per day? Answer: ______ kg

Exercise G – Cooking and Kitchen

Solve cooking-related problems:

1. Recipe Scaling: A recipe for 4 people needs 800 g of flour. How much flour is needed for 10 people? Answer: ______ kg
2. Baking Problem: Mama bakes 6 loaves of bread, each weighing 650 g. What is the total weight? Answer: ______ kg
3. Ingredient Mixing: A cake recipe needs 500 g flour, 300 g sugar, and 200 g butter. What is the total weight of dry ingredients? Answer: ______ g

Quantitative Reasoning

Weight Estimation and Comparison

Exercise H – Estimation Skills

Estimate which is heavier:

1. 5 books vs 1 kg bag of sugar: ______
2. A primary 6 student vs 40 kg: ______
3. 10 pencils vs 100 g: ______
4. A small car vs 1.2 tonnes: ______

Exercise I – Weight Patterns

Complete these weight patterns:

1. Pattern: 100 g, 200 g, 300 g, ______, ______
2. Pattern: 2 kg, 4 kg, 8 kg, ______, ______
3. Pattern: 1.5 kg, 3 kg, 4.5 kg, ______, ______
4. Pattern: 500 g, 1 kg, 1.5 kg, ______, ______

Exercise J – Logic Problems

Use reasoning to solve:

1. Balance Problem: If 3 apples weigh the same as 2 oranges, and 2 oranges weigh 400 g, what does 1 apple weigh? Answer: ______ g
2. Missing Weight: Four items weigh 2 kg, 1.5 kg, 800 g, and an unknown weight. If the total is 5.5 kg, what is the unknown weight? Answer: ______ g
3. Average Weight: Five bags weigh 3 kg, 4 kg, 2.5 kg, 3.5 kg, and 2 kg. What is the average weight? Answer: ______ kg

Answer Key

Exercise A:

1. 4,000 g, 2. 7,500 g, 3. 2.8 kg, 4. 6 kg, 5. 3,000 kg, 6. 4.5 t, 7. 800 g, 8. 12 kg, 9. 2,500,000 g, 10. 0.75 kg

Exercise B:

1. 5 kg 800 g, 2. 8 kg 100 g, 3. 5 kg 300 g, 4. 4 kg 300 g, 5. 4.25 kg, 6. 6,000 g, 7. 3,300 g, 8. 8 kg 500 g

Exercise C:

1. 42 kg, 2. 3,600 g, 3. 3 kg, 4. 300 g, 5. 30 kg, 6. 3 kg, 7. 16 kg, 8. 3 kg

Exercise D:

1. 22 kg, 2. 3 kg, 3. 15 kg, 4. 4 bags, 5. 14 kg

Exercise E:

1. 7 kg 500 g, 2. 33 days (approx), 3. 20 portions, 4. ₦1,000

Exercise F:

1. 85 kg, 2. 500 g, 3. 5.4 kg, 4. 60 kg

Exercise G:

1. 2 kg, 2. 3.9 kg, 3. 800 g

Exercise I:

1. 400 g, 500 g, 2. 16 kg, 32 kg, 3. 6 kg, 7.5 kg, 4. 2 kg, 2.5 kg

Exercise J:

1. 200 g ÷ 3 = 66.7 g, 2. 1,200 g, 3. 3 kg

Exercise K:

1. 2,100 g, 2.2 kg, 2,500 g, 2 kg 800 g
2. 0.9 t, 800 kg, 0.75 t, 650 kg