**Lessons 65 and 66**

**Objective:**

Measure and write metric measures of length as decimal numbers. Convert units of length in the metric system.

Measure and write metric measures of length as decimal numbers. Convert units of length in the metric system.

Math 4 Today

Metric Prefixes

milli=thousandth

centi=hundredth

deci=tenth

deca=ten

hecto=hundred

kilo=thousand

Metric Units

Metric units of length in increasing order:

millimeter

centimeter

decimeter

meter

decameter

hectometer

kilometer

Each unit is 10 times the unit above it. Or each unit is 1/10 the unit below it.

Example 1

Forty centimeters is how many decimeters?

How many millimeters equal 4 decimeters?

Example 2

Eduardo measure his height using a meterstick. He was 1 meter plus 35 centimeters tall. What was Eduardo's height in meters?

Measure Items

Item 1: height of the door:

Item 2: width of the door:

Item 3: height of desk:

Item 4: length of math book:

Foldable: What's It Equal To?

8 mm

8 cm

8 m

8 km

Example 3

.15 m= _____ cm

.123 m = _____ mm

Example 4

.15 m .123 m

.075 m .1 m

.15 m .075 m

.150 m .15 m

Example 5

Write the length of this segment.

a. as a number of millimeters

b. as a number of centimeters

Example 6

To what decimal number is the arrow pointing?

3

4

Lesson Practice

a) Which of these is the most reasonable measurement for the length of an automobile?

a) 4.5 meters b) 4.5 decimeteres

c) 4.5 centimeters d) 4.5 millimeters

b) Alonso is 1 meter plus 43 centimeters tall. Use a decimal number to write Alonso's height in meters.

c) A ruler is about 30 centimeters long. About how many decimeters long is a ruler?

Page 420

**Reflections:**

The length of a sticky note measures 77 millimeters. Express this length in meters. Explain your thinking. Include an equation with an exponent in your explanation.

The length of a sticky note measures 77 millimeters. Express this length in meters. Explain your thinking. Include an equation with an exponent in your explanation.

1) Write an expression for 2) Write <, >, or = to make the

the calculation the

sum of the

statement true.

products of 4 and 3 and 1 and 1.

16.272 1.672

3) 824 x 34= 4) Find the area of the rectangle.

3/10 ft.

5 ft.

2.638 m = ______________ mm 2.638 x 10= 2,638

7 cm = ______________ m

39 mm = _______________ m

0.08 m = ______________ mm

0.005 m = _____________ cm

Yi Ting’s height is 1.49 m. Express this measurement in millimeters. Explain your thinking. Include an equation wiht an exponent in your explanation.

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