1. The Metric System
2nd Year Maths

2. Facts about the metric system:
The metric system is an international decimalised system of measurement that was originally based on the mètre des archives and the kilogramme des archives introduced by France in 1799.
The United States is the only industrialised country that does not use the metric system as its official system of measurement.

3. Ireland & the Metric System:
Ireland has been fully metric since 2005.
It is principally due to Irish membership in the European Union (EU) that metric units were introduced.
Since 2005 all new cars sold in Ireland have had speedometers that display only kilometres per hour.
Ireland traditionally used miles, yards, feet and inches. These are still used in many situations.

4. Centimetres (cm) / Millimetres (mm)
Examples
Metric System
Centimetres (cm) / Millimetres (mm)
Imperial System
Inches / 1/8 inches

5. Examples
500 millilitre (ml)
2 litre (l)

7. Examples

8. Conversion Table 1 km (km) = 1000 metres (m)
1 metre (m) = 100 centimetres (cm)
1 centimetre (cm) = 10 millimetres (mm)

9. Questions: Express the total length of the pitch (145m) in Kilometres
Centimetres
Millimetres
A player ran from the end line to the 45 metre line and back again. Express the distance he ran in:
Millimetres:
A player sprinted from the end line to the 20m line 5 times.
What was the total distance he ran in metres?
If it took 40 seconds, what was his speed in metres per second (m/s)?
Speed =

10. Express the total length of the pitch (145m) in
Kilometres Answer: 0.145km
Centimetres Answer: 14500cm
Millimetres Answer: mm
A player ran from the end line to the 45 metre line and back again. Express the distance he ran in:
Kilometres Answer: 0.09km
Centimetres Answer: 9000cm
Millimetres: Answer: mm
A player sprinted from the end line to the 20m line 5 times.
What was the total distance he ran in metres? Answer: 100m
If it took 40 seconds, what was his speed in metres per second (m/s)? Answer: 2.5 m/sec

11. Q1. Express the three distances in:
Metres
Centimetres
Q2. How many metres would you have driven if you went to Monaghan and back?
Q3. How long would it take you to drive a return trip to Derry if you were travelling at an average speed of 58km/h?
Time =

12. Q1. Express the three distances in:
Metres
Answer: m, 99000m, 19000m
Centimetres
Answer: 20,300,000cm, 9,900,000cm, 1,900,000cm
Q2. How many metres would you have driven if you went to Monaghan and back?
Answer: 108,000 metres
Q3. How long would it take you to drive a return trip to Derry if you were travelling at an average speed of 58km/h?
Answer: Time =
Time = 7 hours

13. Units of Mass (Weight) 1 tonne = 1000 kilograms (kg)
Conversion Table
1 tonne = 1000 kilograms (kg)
1 kilogram (kg) = 1000 grams (g)
1 gram (g) = 1000 milligrams (mg)

14. Examples
1 kilogram (kg)
3428 kilograms (kg)

15. Examples 8.5 grams (g) 34.5 milligrams (mg)
The amount of caffeine in Coca-Cola.

16. The amount of caffeine in a can of Red Bull
Examples
80 milligrams (mg)
The amount of caffeine in a can of Red Bull

17. Questions:
You are shopping online and have to pay extra for postage on your parcel. Your parcel weighs 4.25kg. The shipping cost is 20 cent per every 125g of weight.
Complete the following:
Express the weight of the parcel in:
Grams
Tonnes
Milligrams
2. Calculate the total cost of
shipping the product.
Answers:
Q1: 4250g tonnes 4,250,000mg
Q2: 4.25kg = 4250g
4250g ÷ 125g = 34
34 x 20 cent = 680c
680cent = €6.80

18. You are going on holidays and want to check in a bag
You are going on holidays and want to check in a bag. Ryanair allow a maximum of 20kg on board. They charge an excess fee of €20 per kg if your bag is overweight. The weight of the bag show up at 23,250g.
Express the weight of the bag in terms of:
Milligrams (mg)
Tonnes
Kilograms (kg)
2. If the basic fee for checking in baggage is €55. Calculate the total fee you will have to pay to check in.
Answers:
Q1: (i) 23,250,000mg
(ii) tonnes
(iii) 23.25kg
Q2: €50 + (3.25kg x €20) =
€50 + €65 = Total of €115