Lesson Notes By Weeks and Term v5 - Grade 4

Lesson Video

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Performance objectives

• Measure and compare lengths (m, cm)
• Estimate, measure, and compare mass (kg, g)
• Estimate, measure, and compare capacity (l, ml)
• Convert between these units
• Solve word problems involving measurement

Lesson summary

This week, we will be exploring the world of measurement, specifically focusing on length, mass, and capacity. Measurement is how we describe the size, weight, and volume of things. Understanding measurement is incredibly important in our daily lives.

Think about it: when you go to the shop to buy sweets, you need to know how much they weigh. When you're building a sandcastle at the beach, you need to measure how long and wide it is. And when you're making cool drink for your friends, you need to know how much juice to pour in! In South Africa, whether you are helping your parents measure mielie meal for pap, or working with distances on a map, measurement is all around us.

Lesson notes

Length: Length is the measurement of how long something is. We use different units to measure length, depending on the size of the object.

Centimetre (cm): A centimetre is a small unit of length. Think of the width of your little finger. 100 centimetres make 1 metre.

Metre (m): A metre is a larger unit of length. Think of the length of a cricket bat. 1 metre is equal to 100 centimetres.

Conversion: To convert between metres and centimetres, we use the following: 1 m = 100 cm To convert metres to centimetres, we multiply by

1

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0. To convert centimetres to metres, we divide by

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0. Example 1: How many centimetres are there in 3 metres?

Solution: Since 1 m = 100 cm, then 3 m = 3 x 100 cm = 300 cm Answer: There are 300 centimetres in 3 metres.

Example 2: How many metres are there in 500 centimetres?

Solution: Since 100 cm = 1 m, then 500 cm = 500 ÷ 100 m = 5 m Answer: There are 5 metres in 500 centimetres.

Mass: Mass is the measurement of how heavy something is. We use different units to measure mass, depending on the weight of the object.

Gram (g): A gram is a small unit of mass. Think of the weight of a paperclip. 1000 grams make 1 kilogram.

Kilogram (kg): A kilogram is a larger unit of mass. Think of the weight of a bag of sugar. 1 kilogram is equal to 1000 grams.

Conversion: To convert between kilograms and grams, we use the following: 1 kg = 1000 g To convert kilograms to grams, we multiply by

1

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0. To convert grams to kilograms, we divide by

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0. Example 3: How many grams are there in 2 kilograms?

Solution: Since 1 kg = 1000 g, then 2 kg = 2 x 1000 g = 2000 g Answer: There are 2000 grams in 2 kilograms.

Example 4: How many kilograms are there in 4000 grams?

Solution: Since 1000 g = 1 kg, then 4000 g = 4000 ÷ 1000 kg = 4 kg Answer: There are 4 kilograms in 4000 grams.

Capacity: Capacity is the amount of liquid a container can hold. We use different units to measure capacity, depending on the size of the container.

Millilitre (ml): A millilitre is a small unit of capacity. Think of a single drop of water. 1000 millilitres make 1 litre.

Litre (l): A litre is a larger unit of capacity. Think of a bottle of juice. 1 litre is equal to 1000 millilitres.

Conversion: To convert between litres and millilitres, we use the following: 1 l = 1000 ml To convert litres to millilitres, we multiply by

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0. To convert millilitres to litres, we divide by

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0. Example 5: How many millilitres are there in 5 litres?

Solution: Since 1 l = 1000 ml, then 5 l = 5 x 1000 ml = 5000 ml Answer: There are 5000 millilitres in 5 litres.

Example 6: How many litres are there in 3000 millilitres?

Solution: Since 1000 ml = 1 l, then 3000 ml = 3000 ÷ 1000 l = 3 l Answer: There are 3 litres in 3000 millilitres. Guided Practice (With Solutions)

Question 1: A table is 2 metres long. How long is the table in centimetres?

Solution: We know that 1 metre is equal to 100 centimetres (1 m = 100 cm). To find the length of the table in centimetres, we multiply the length in metres by 100. 2 m x 100 cm/m = 200 cm Therefore, the table is 200 centimetres long.

Question 2: A bag of potatoes weighs 5 kilograms. How much does the bag of potatoes weigh in grams?

Solution: We know that 1 kilogram is equal to 1000 grams (1 kg = 1000 g). To find the weight of the potatoes in grams, we multiply the weight in kilograms by 1000. 5 kg x 1000 g/kg = 5000 g Therefore, the bag of potatoes weighs 5000 grams.

Question 3: A bottle contains 1.5 litres of water. How much water is in the bottle in millilitres?

Solution: We know that 1 litre is equal to 1000 millilitres (1 l = 1000 ml). To find the amount of water in millilitres, we multiply the amount in litres by 1000. 1.5 l x 1000 ml/l = 1500 ml Therefore, there are 1500 millilitres of water in the bottle.

Question 4: John ran 800 centimetres in a race. How many meters did John run?

Solution: We know that 100 centimetres is equal to 1 metre (100 cm = 1 m) To find the length of the race in meters, we divide the length in centimeters by 100. 800 cm / 100 cm/m = 8 m Therefore, John ran 8 meters. Independent Practice (Questions Only) A piece of rope is 4 metres long. How long is the rope in centimetres? A packet of sugar weighs 1.2 kilograms. How much does the packet of sugar weigh in grams? A jug contains 2.7 litres of juice. How much juice is in the jug in millilitres? A pencil is 15 centimetres long. How long is the pencil in metres? A brick weighs 2500 grams. How much does the brick weigh in kilograms? A glass contains 250 millilitres of milk. How much milk is in the glass in litres? Thando walked 3 km to school. Knowing that 1 km = 1000 m, how many meters did Thando walk? A farmer harvests 5 tons of mielies. Knowing that 1 ton = 1000 kg, how many kilograms of mielies did the farmer harvest? A swimming pool holds 8000 liters of water. How many kiloliters does the pool hold? Knowing that 1 kiloliter = 1000 liters. A baker uses 500 g of flour for each loaf of bread.