Length, Weight, Capacity, Time & Money Chapter Notes | Mathematics Olympiad Class 4 PDF Download

Measurement is how we find out the size, amount, or quantity of something. In our daily lives, we measure many things, such as length, weight, capacity, time, and money. Let's understand what these are and how measurement works for each one.

Length

Units of Length:

• Millimeter (mm): For very tiny things, like the thickness of a paper.
• Centimeter (cm): For small objects, like a book or a phone.
• Meter (m): For bigger things, like the length of a room or a playground.
• Kilometer (km): For long distances, like the distance between two cities.

Tools:

• Ruler: For measuring small objects (in cm or inches).
• Measuring tape: For measuring bigger things, like your height or the length of a table.

Example Question 1:
Question: What is the length of a pencil that measures 15 cm?
Answer: The pencil is 15 cm long.

Example Question 2:
Question: If you walk 2 km to school and back home, how many kilometers do you walk in total?
Solution:
Walking to school: 2 km
Walking back home: 2 km
Total distance = 2 km + 2 km = 4 km
Conversion:
You might need to convert one unit to another. For example:

• 100 cm = 1 meter
• 1000 meters = 1 kilometer

Example Question 3:
Question: How many centimeters are in 3 meters?
Solution:
1 meter = 100 cm
3 meters = 3 × 100 = 300 cm

Weight

Units of Weight:

• Gram (g): For light objects, like a pencil or an apple.
• Kilogram (kg): For heavier objects, like a watermelon or a bag of rice.

Tools:

• Weighing scale: For finding out how heavy something is.

Example Question 1:
Question: A banana weighs 120 grams. How many bananas will weigh 360 grams?
Solution:
One banana = 120 grams
360 grams ÷ 120 grams = 3 bananas
Conversion:
You might need to convert grams to kilograms:
1000 grams = 1 kilogram

Example Question 2:
Question: How many grams are in 2 kilograms?
Solution:
1 kilogram = 1000 grams
2 kilograms = 2 × 1000 = 2000 grams

Example Question 3:
Question: If a bag of apples weighs 1.5 kg and a bag of oranges weighs 1 kg, what is the total weight?
Solution:
Apples: 1.5 kg
Oranges: 1 kg
Total weight = 1.5 kg + 1 kg = 2.5 kg

Capacity

Units of Capacity:

• Milliliter (ml): For small amounts of liquid, like a spoon of medicine.
• Liter (L): For larger amounts, like a bottle of water or a bucket of milk.

Tools:

• Measuring cup: For measuring small amounts of liquids.
• Measuring jug: For bigger amounts of liquids, like water or juice.

Example Question 1:
Question: If a bottle holds 500 ml of water, how many bottles will fill up a 1-liter jug?
Solution:
1 liter = 1000 ml
Number of bottles = 1000 ml ÷ 500 ml = 2 bottles
Conversion:
You might need to convert milliliters to liters:
1000 milliliters = 1 liter

Example Question 2:
Question: How many milliliters are in 3 liters?
Solution:
1 liter = 1000 ml
3 liters = 3 × 1000 = 3000 milliliters

Time

Units of Time:

• Seconds (s): For very short periods (like how long you can hold your breath).
• Minutes (min): For everyday tasks (like brushing your teeth or doing homework).
• Hours (h): For longer periods (like a school day).

Tools:

• Clocks and watches: To tell the time of day.
• Stopwatch: To measure how long something takes.

Example Question 1:
Question: If you spend 30 minutes watching TV and 20 minutes reading, how much time did you spend in total?
Solution:
Watching TV: 30 minutes
Reading: 20 minutes
Total time = 30 min + 20 min = 50 minutes

Conversion:
You might need to convert time units:

• 60 seconds = 1 minute
• 60 minutes = 1 hour

Example Question 2:
Question: How many minutes are in 2 hours?
Solution:
1 hour = 60 minutes
2 hours = 2 × 60 = 120 minutes

Money

Units of Money:

• Cents/Paise: For small amounts of money.
• Dollars/Rupees: For larger amounts of money.

Example Question 1:
Question: If you have 50 rupees and you buy a toy for 30 rupees, how much money do you have left?
Solution:
Starting money = 50 rupees
Cost of toy = 30 rupees
Money left = 50 rupees – 30 rupees = 20 rupees

Example Question 2:
Question: If a pencil costs 5 rupees and you want to buy 4 pencils, how much money do you need?
Solution:
Cost of 1 pencil = 5 rupees
Cost of 4 pencils = 4 × 5 = 20 rupees

Recap:

• Length is how long or short something is, measured in mm, cm, m, or km.
• Weight is how heavy or light something is, measured in g or kg.
• Capacity is how much liquid something holds, measured in ml or L.
• Time is how long something takes, measured in seconds, minutes, or hours.
• Money is how much something costs, measured in cents/paise and dollars/rupees.

Each measurement has tools and units that help us find out exact amounts, making life easier and more organized!