Metric Units

 

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🔹 1. What are Metric Units?

Metric units are standard units of measurement used around the world for measuring length, mass, time, and capacity.

The metric system is based on powers of 10, making it easy to convert between units.

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🔹 2. Metric Units of Length

We use these units to measure how long, wide, or tall something is.

Unit	Symbol	Use
millimeter	mm	very small objects (e.g. thickness of a coin)
centimeter	cm	small lengths (e.g. pencil)
meter	m	standard unit for length (e.g. room size)
kilometer	km	long distances (e.g. distance between towns)

🔁 Conversions:

• 1 cm = 10 mm

• 1 m = 100 cm

• 1 km = 1000 m

✏️ Examples:

• A notebook is about 30 cm long.

• A road between two towns may be 12 km long.

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🔹 3. Metric Units of Mass (Weight)

We use these units to measure how heavy something is.

Unit	Symbol	Use
milligram	mg	very light objects (e.g. medicine)
gram	g	small items (e.g. sugar, fruits)
kilogram	kg	heavier items (e.g. people, bags)
tonne	t	very heavy items (e.g. trucks, machinery)

🔁 Conversions:

• 1 g = 1000 mg

• 1 kg = 1000 g

• 1 tonne = 1000 kg

✏️ Examples:

• An apple weighs about 200 g.

• A bag of cement weighs 50 kg.

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🔹 4. Metric Units of Time

We use these units to measure duration or how long something takes.

Unit	Use
second (s)	very short events
minute (min)	60 seconds
hour (h)	60 minutes
day	24 hours
week	7 days
month	~30 or 31 days
year	12 months or 365 days

✏️ Examples:

• A short video clip may last 30 seconds.

• A class may last 40 minutes.

• A movie is about 2 hours long.

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🔹 5. Metric Units of Capacity (Volume)

We use these units to measure how much space a liquid takes.

Unit	Symbol	Use
milliliter	mL	small amounts (e.g. medicine)
liter	L	everyday liquid measures (e.g. water, juice)
kiloliter	kL	large amounts (e.g. tank of water)

🔁 Conversions:

• 1 L = 1000 mL

• 1 kL = 1000 L

✏️ Examples:

• A soft drink bottle has 500 mL of soda.

• A water tank holds 2,000 L (2 kL).

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✅ Summary Table

Measurement	Units	Conversion Example
Length	mm, cm, m, km	1 km = 1000 m
Mass	mg, g, kg, t	1 kg = 1000 g
Time	s, min, h, day	1 min = 60 s
Capacity	mL, L, kL	1 L = 1000 mL

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