Lesson Notes By Weeks and Term v5 - Grade 4
Measurement: length, mass and capacity (Grade 4) – Week 2 focus
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Measurement: length, mass and capacity (Grade 4) – Week 2 focus
Download the Lessonotes Mobile South Africa app for faster lesson access on Android and iPhone.
Subject: Mathematics
Class: Grade 4
Term: 3rd Term
Week: 2
Theme: General lesson support
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This week, we'll continue our exploration of measurement, focusing on length, mass, and capacity. Understanding these measurements is crucial for everyday life. From measuring ingredients for pap and vleis to figuring out how much water is needed for a bath, or even how tall a building is, measurement helps us make sense of the world around us. We'll build on what we learned last week and tackle more complex problems. Specifically, we will be comparing different units of measurement and solving problems in context.
Length: Length measures how long something is. We use different units of length depending on the size of the object we're measuring.
Millimetre (mm): A very small unit, like the thickness of a few sheets of paper.
Centimetre (cm): A bit bigger, about the width of your pinky finger. 1 cm = 10 mm.
Metre (m): A good unit for measuring the height of a door or your own height. 1 m = 100 cm = 1000 mm.
Kilometre (km): Used for measuring long distances, like the distance between towns. 1 km = 1000 m. Conversion
Examples: Example 1: How many centimetres are in 3 metres? We know that 1 m = 100 cm. So, 3 m = 3 x 100 cm = 300 cm.
Example 2: How many millimetres are in 5 centimetres? We know that 1 cm = 10 mm. So, 5 cm = 5 x 10 mm = 50 mm.
Example 3: How many metres are in 2 kilometres? We know that 1 km = 1000 m. So, 2 km = 2 x 1000 m = 2000 m.
Mass: Mass measures how heavy something is. We use different units of mass depending on how heavy the object is.
Gram (g): A small unit, like the mass of a paperclip or a small sweet.
Kilogram (kg): A bigger unit, like the mass of a bag of sugar or a loaf of bread. 1 kg = 1000 g. Conversion
Examples: Example 1: How many grams are in 2 kilograms? We know that 1 kg = 1000 g. So, 2 kg = 2 x 1000 g = 2000 g.
Example 2: A bag of apples weighs 3.5 kg. How many grams is that? We know that 1 kg = 1000 g. So, 3.5 kg = 3.5 x 1000 g = 3500 g.
Capacity: Capacity measures how much a container can hold.
Millilitre (ml): A small unit, like the amount of water in a small medicine spoon.
Litre (l): A bigger unit, like the amount of water in a bottle of cool drink or a carton of milk. 1 l = 1000 ml. Conversion
Examples: Example 1: How many millilitres are in 4 litres? We know that 1 l = 1000 ml. So, 4 l = 4 x 1000 ml = 4000 ml.
Example 2: A bottle of juice contains 1.5 litres. How many millilitres is that? We know that 1 l = 1000 ml. So, 1.5 l = 1.5 x 1000 ml = 1500 ml. Guided Practice (With Solutions)
Question 1: A piece of rope is 2 metres long. Thando cuts off 75 centimetres. How long is the remaining rope in centimetres?
Solution: First, convert the length of the rope to centimetres: 2 m = 2 x 100 cm = 200 cm. Then, subtract the length that Thando cut off: 200 cm - 75 cm = 125 cm.
Answer: The remaining rope is 125 cm long.
Question 2: A bag of oranges weighs 1.8 kg. A bag of apples weighs 900 g. Which bag is heavier, and by how much (in grams)?
Solution: Convert the weight of the oranges to grams: 1.8 kg = 1.8 x 1000 g = 1800 g. Subtract the weight of the apples from the weight of the oranges: 1800 g - 900 g = 900 g.
Answer: The bag of oranges is heavier by 900 g.
Question 3: A jug contains 2.5 litres of water. Sipho drinks 600 ml of water from the jug. How much water is left in the jug (in millilitres)?
Solution: Convert the amount of water in the jug to millilitres: 2.5 l = 2.5 x 1000 ml = 2500 ml.
Subtract the amount of water Sipho drank: 2500 ml - 600 ml = 1900 ml.
Answer: There are 1900 ml of water left in the jug.
Question 4: A table is 120cm long. How long is it in meters?
Solution: We know 100 cm = 1 meter So 120 cm = 120/100 meters = 1.2 meters Answer: the table is 1.2 meters long. Independent Practice (Questions Only) A fence is 50 metres long. How long is it in centimetres? A packet of sugar weighs 2.5 kg. How many grams does it weigh? A bucket contains 8 litres of water. How many millilitres does it contain? John walks 1.5 kilometres to school. His friend, Mary, walks 900 metres to school. Who walks further, and by how much (in metres)? A roll of cloth is 15 metres long. A dressmaker uses 350 cm of the cloth to make a dress. How much cloth is left on the roll (in centimetres)? Sipho buys two bags of potatoes. One bag weighs 3 kg, and the other weighs 1500 g. What is the total mass of the potatoes in kilograms? A container holds 3 litres of cool drink. Sam pours out 800 ml of cool drink for his friends. How much cool drink is left in the container (in millilitres)? A ruler is 30cm long. How many rulers would you need to measure a desk that is 1.8 meters long? A taxi travels 245 km. How many meters is that? Sarah's height is 135cm. Convert her height into meters.