Brain Teaser

• How can the numbers 2 2 2 be arranged to equal 3?

• Hint: think order of operations.

Solution

•2 + (2÷2)

•2 + 1 = 3

Measurement: The Metric System

Lesson 1-8

Metric System• The metric system is based on a unit

that corresponds to a certain kind of measurement

• Length = meter• Volume = liter• Weight (Mass) = gram

• Prefixes plus base units make up the metric system – Example:

• Centi + meter = Centimeter• Kilo + liter = Kiloliter

•So if you needed to measure length you would choose meter as your base unit–Length of a tree branch–Length of a room –Length of a table

•But what if you need to measure a longer distance, like from your house to school?

– Instead of measuring in meters, we would use kilometers.

–Kilometers are larger units used to measure longer distances.

Metric System• The three prefixes that we will use

the most are:– kilo– centi– milli

kilo hecto deca

Base Units

metergramliter

deci centi milli

How do we remember the order?

•King Henry Dances Until Dragons Change Music.

• These prefixes are based on powers of 10. What does this mean?–From each prefix every “step” is either:•10 times larger

or•10 times smaller

kilo hecto deca

Unitsmetergramliter

deci centi milli

– Centimeters are 10 times larger than millimeters so it takes more millimeters for the same length

– 1 centimeter = 10 millimeters

Example not to scale

1 mm

1 mm

1 mm

1 mm

1 mm

1 mm

1 mm

1 mm

1 mm

1 mm

1 cm

40

41

41

40

• An easy way to move within the metric system is by moving the decimal point one place for each “step”

Example: change meters to centimeters

kilo hecto deca

meterliter

gram

deci centi milli

It takes 2 moves to get from meters to centi. So we move the decimal 2 places.

Metric System• If you move to the left in the diagram,

move the decimal to the left

• If you move to the right in the diagram, move the decimal to the right

kilo hecto deca

meterliter

gram

deci centi milli

• Now let’s try an example.152.7 meters = _____ kilometers

kilo hecto deca

meterliter

gram

deci centi milli

So for every “step” from the base unit to kilo, we move the decimal 1 place

to the left (the same direction as in the diagram

below) 152.7 meters = .1527 kilometers

•Now let’s start from centimeters and convert to kilometers

400000 centimeters =______ kilometersMove the decimal 5 places to the left.400000 centimeters = 4.00000

kilometers

kilo hecto deca

meterliter

gram

deci centi milli

• Now let’s start from meters and convert to centimeters

5 meters = ______centimeters

kilo hecto deca

meterliter

gram

deci centi milli

kilo hecto deca

meterliter

gram

deci centi milli

• Now let’s start from kilometers and convert to meters

.3 kilometers = ____meters

500

300

Metric System• Summary

– Base units in the metric system are meter, liter, gram

– Metric system is based on powers of 10– For conversions within the metric system,

each “step” is 1 decimal place to the right or left

– Move the decimal to the right or the left the same number of spaces on the diagram.

kilo hecto deca

meterliter

gram

deci centi milli

Summary

• King Henry Dances Until Dragons Change Music.

Your homework. Lesson 1-8 #2-26

evens!