Measurement 1

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Measurement Part One

Systems of Measurement

Every day we read or hear numbers that relate to the world around us. These numbers are often descriptions of things. For example, a common object like a car can be described using numbers in many ways:

How far has the car traveled?

How old is the car?

How much is the car worth?

How much does the car weigh?

How hot or cold is the car right now?

124,349 kilometres

6 years

$7,225

4,700 pounds

21ºC

Whenever we describe things using numbers, we are using measurement. Often measurement can be done in more than one way. For example, the age of the car can be measured using years or months.

DESCRIPTION QUALITY BEING

MEASURED

MEASURED

AMOUNT

ALTERNATIVE

AMOUNT

How far has the car traveled?

How old is the car?

Distance

Time

124,349 kilometres 77,718 miles

6 years 72 months

How much is the car worth? Value $7,225

722,500¢

How much does the car weigh?

How hot or cold is the car?

Weight (or mass)

Temperature

4,700 pounds

21º Celsius

2136 kilograms

70º Fahrenheit

Usually, one way of measuring is the most common for a certain situation. The age of person is given in years, unless the person is very young, and then months or days would be used. The weight of a person in this country is usually given in pounds, but in many other countries people use kilograms. We often need to understand the situation in order to know what type of measurement to use.

We sometimes talk about using the Metric System of Measurement and the Imperial System of

Measurement. Canada used the Imperial System until the early 1970’s, but now we use mainly the Metric System. Common exceptions to using metric are the weight of a person (usually measured in pounds) and height of a person (usually measured in feet and inches).

1

Types and Units of Measurement

The chart below shows the units that are typically used for various types of measurement in

Canada and some common instruments used for measuring. This list is not complete.

Units System Measuring instrument Type

Distance kilometers metres centimeters feet and inches metric metric metric

Imperial car odometer carpenter’s measuring tape ruler ruler or tape

Time years, months, days hours, minutes, seconds both both calendar clock, stopwatch

Speed kilometres per hour metres per second litres and millilitres cups metric metric metric

Imperial car speedometer measuring cup measuring cup

Volume

Mass or weight

Value

Temperature kilograms pounds dollars and cents degrees Celsius metric

Imperial both metric grocery store scale bathroom scale usually counted manually thermometer

2

Distance

This ruler has both metric and Imperial scales. The top scale uses the centimetre as the unit of measurement, and the bottom scale uses the inch.

The left arrow above shows a distance of one centimetre from the 0 mark and the other arrow shows a distance of 6 centimetres from 0. One centimetre is about the width of a person’s baby finger.

Each centimetre (cm) is divided into 10 parts called millimetres (mm). There are 10 millimetres in 1 centimetre. One millimetre is about the width of a pencil lead.

The length of the entire pencil shown is 8 centimetres. Since each centimetre contains 10 millimetres, the length of the pencil can also be written as 80 millimetres.

The length of the nail below is 14.7 cm or 147 mm.

Notice that if we multiply the number of centimetres by 10 we get the number of millimetres. If we divide the number of mm by 10 we get the number of cm.

3

Measurement Practice

Measure the length of each of the following objects using a ruler and fill in the blanks with the correct numbers.

_____ cm _____ mm

_____ cm

_____ cm

_____ cm

_____ cm

_____ mm

_____ mm

_____ mm

_____ mm

4

Deca

Hecto

Kilo

Distance Units in the Metric System

Find a metre stick in your classroom and examine it. The stick is one metre long.

How many centimetres are on the stick? (1 cm is about the width of a small finger)

How many millimetres are on the stick? (1 mm is about the width of a pencil lead)

______

______

How many decimetres are on the stick? (1 decimetre has 10 centimetres and is about the width of a person’s hand including the thumb)

You should be able to see that the metre stick has the following lengths:

1 metre = 10 decimetres = 100 centimetres = 1000 millimetres

The units can be written as follows:

______

1 m = 10 dm = 100 cm = 1000 mm

The names of the units in metric are made up of the word “metre” and a prefix. Each prefix means a particular value compared to the metre, which is the base unit.

Prefix Meaning

Milli + metre = millimetre (mm)

1

1000

or 0.001 of a metre

Centi + metre = centimetre (cm)

1

100

or 0.01 of a metre

Deci + metre = decimetre (dm)

1

10

or 0.1 of a metre

+

+

+ metre metre metre

=

=

= metre (m) decametre (dam) hectometre (hm) kilometre (km)

1 metre

10 metres

100 metres

1000 metres

5

Converting Distance Measurements Within the Metric System

To help you change a value from one metric unit of measurement to another, the following

Metric Staircase is useful.

X 10

X 10 kilo (k)

X 10 kilometre hecto (h)

X 10 hectometre deca (da)

X 10 decametre

Base Unit X 10 metre deci (d) decimetre centi (c) centimetre milli (m) millimetre

Kilometre, at the top, is the largest unit on the staircase. Millimetre, at the bottom, is the smallest. Because kilometres are so large compared to millimetres, it takes one million millimetres to equal a single kilometre.

1 km = 1,000,000 mm

Each step down is a multiplication by 10. As you know, multiplying by 10 is simply moving the decimal one space to the right.

1 km = 10 hm = 100 dam = 1000 m = 10,000 dm = 100,000 cm = 1,000,000 mm

Examples:

3 km = 30 hm = 300 dam = 3000 m = 30,000 dm = 300,000 cm = 3,000,000 mm

12 km = 120 hm = 1200 dam = 12,000 m = 120,000 dm = 1,200,000 cm = 12,000,000 mm

0.002 km = 0.02 hm = 0.2 dam = 2 m = 20 dm = 200 cm = 2000 mm

Example: Change 5 hectometres into metres. 5 hm = ??? m

Solution: Starting at hectometres, how many steps do you take to get to metres? Two steps to the right (down the stairs) means to multiply by 10 twice:

5 hm = 50 dam = 500 m

6

Example: Change 0.54 kilometres into decimetres. 0.54 km = ??? dm

Solution: Starting at kilometers, how many steps do you take to get to decimetres? Four steps down means to multiply by 10 four times:

0.54 km = 5.4 hm = 54 dam = 540 m = 5400 dm

Example: How many decimetres are in 3.052 decametres?

Solution: 3.052 dam = ??? dm

Starting at decametres, move two steps to the right. Because you moved two steps to the right, simply move the decimal point two places to the right.

3.052 dam = 305.2 dm

To change a smaller unit into a larger unit, start at the smaller unit and keep dividing by 10 until you reach the larger unit. As you know, the shortcut for dividing by 10 is to move the decimal point one place to the left.

÷ 10

÷ 10 kilo (k)

÷ 10 kilometre hecto (h)

÷ 10 hectometre deca (da)

÷ 10 decametre Base Unit

÷ 10 metre deci (d) decimetre centi (c) centimetre milli (m) millimetre

For example, to change 10 millimetres into metres, begin at mm and move left (up) three steps.

10 mm = 1 cm = 0.1 dm = 0.01 m

Examples: 43 cm = ??? hm

Solution: 43 cm = 4.3 dm = 0.43 m = 0.043 dam = 0.0043 hm

Because hectometres is four steps to the left of centimetres, the shortcut is to move the decimal four places to the left.

7

Practice Converting Metric Distances

Remember: To change from a larger unit to a smaller unit, multiply. To change from a smaller unit to a larger unit, divide.

Moving to the right on the staircase means you need to move the decimal to the right.

Moving to the left on the staircase means you need to move the decimal to the left.

Changing from a smaller unit to larger unit. Changing from a larger unit to a smaller unit.

1.

4.5 km = __________ hm

2.

3.

63.2 dam = __________m

74.02 hm = __________cm

13.

14.

15.

78 cm = __________dm

8579 mm = __________hm

41 hm = __________km

16. 0.5 dam = __________hm

7.

8.

4.

5.

6.

9 km = __________m

0.24 cm = __________mm

0.5 dm = __________cm

4.55 m = __________mm

98 m = __________dm

9.

0904 dm = __________mm

10.

77 dam = __________dm

11.

0.0002 cm = __________mm

12.

0.005 hm = __________ cm

Convert the following.

1.

3855 cm = __________hm

2.

6 dm = __________mm

3.

354 mm = __________m

4.

0.25 km = __________hm

17.

18.

19.

20.

21.

22.

23.

24.

5.

6.

7.

8.

0.003 m = __________dam

4889 cm = __________hm

780 dm = __________km

15.2 dam = __________km

5.6 cm = __________m

0.88 mm = __________dm

4899.02 mm = __________km

7 dam = __________km

0.05 dam = __________dm

97.05 m = __________mm

47 km = __________dam

3.2 hm = __________km

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Complete the following

1. 7cm 4mm = ___________mm

2. 5m 9cm = _____________cm

3. 4m 8dm 2cm = _________cm

4.

5.

3km 2m = ________km

4km 17m 52cm = ______m

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