Download NUMBER LINES FOR HUNDREDTHS 4.NF.6

NUMBER LINES FOR HUNDREDTHS 4.NF.6
Forming Number Lines for Decimals and Mixed Decimals
Purpose:
To connect a visual model for hundredths to a decimal number line with hundredths
Materials:
Decimal Squares, Hundredths Decimal Number Line activity sheet (attached), and pencils
TEACHER MODELING/STUDENT COMMUNICATION
Activity 1 Find points on hundredths number line for visual models
Decimal
Squares
Hundredths
Decimal
Number
Line
pencils
1. Students need decimal squares and copies of the Hundredths Decimal Number Line.
 Select any green hundredths square. How many equal parts is it divided into? (100)
What is the decimal for 1 of these 100 parts? (.01)
 Look at your Hundredths Number Line. What do you notice about this number
line? (It has the numbers 0.0, 1.0, 2.0, and 3.0 and 10 spaces between these
pairs of numbers.)
 The part of the number line between 0.0 and 1.0 is divided into how many equal
parts? (100) What is the decimal for 1 part out of 100? (.01, so each small space on
the hundredths line corresponds to a small square on the green hundredths squares.)
Find the green hundredths square with 40 parts
shaded. What is the decimal for the shaded amount
of this square? (.40) Place this square above your
number line so that the shading starts above the
point for 0.0. Notice that the 40 hundredths of this
square correspond to 40 small spaces on the number
line, and each small space on the line represents onehundredth. Why is the decimal .4 written below the
line rather than the decimal .40? (Because .4 = .40,
that is, 4 parts of a red square is equal to 40 parts of
a green square.)
 Find a green square with 65 parts shaded out of 100. What is the decimal for this
square? (.65) Without placing this square on the number line, how can the decimal
for .65 be found quickly? (Go to .6 on the number line and then count off 5 small
hundredths spaces.
 How can the decimals on the number line be found for the following hundredths
squares?
(1) A square with 37 parts shaded out of 100? (Go to the mark for .3 and then count off
7 small hundredths spaces.)
(2) One whole square and a square with 83 parts shaded out of 100? (Go to the mark for
1.0, then continue to the mark for 1.8, and then count off 3 small hundredths spaces.)
(3) Two whole squares and square with 48 parts shaded out of 100? (Go to the mark for
2.0, then continue to the mark for 2.5, and then count back 2 small hundredths spaces.)
Activity 2 Measuring length with the hundredths number line
Hundredths
Number Lines
pencils
 Use your number line to measure the length of a pencil or pen to the nearest mark
on the line. (This pencil has a length of 1.58 units to the closest space on the
hundredths line. When this pencil was measured using the tenths number line in the
previous lesson, its length was 1.6 units to the closest space on the tenths line.
Discuss the idea of precision, the more parts the unit is divided into (0.0 to 1.0, or
1.0 to 2.0, etc.) the more precise the measurement will be.

Use the hundredths number line to measure the length of a paperclip. (This
paperclip has a length of .47 units to the closest space on the hundredths line. When
this paperclip was measured using the tenths number line in the previous lesson, its
length was .5 units to the nearest tenth because it was about halfway between .4 and
.5 and the height was rounded up to .5 unit.)
 Use your hundredths number line to measure the length of other objects. For
example, the height and width of a standard sheet of paper. (The height is 2.78 units
and the width is 2.16 units to the nearest hundredths on the line. Note: The number
lines can be cut out along the dashed lines and students can write their names on
back. Students will need these numbers lines in one of the two activity sheets below.
Activity 3 Number Lines Game
Each group will need the hundredths number line, the decimal squares for tenths and
hundredths, and some markers. Only the interval from 0.0 to 1.0 on the number line will be
used. Place the squares face down. Each player in turn selects a square and places a marker
on the number line above the decimal for the square. The first player to place three markers
in one of the ten intervals from 0.0 to 1.0 wins the game. For example, .4, .45, and .5.
INDEPENDENT PRACTICE and ASSESSMENT
Worksheets 4.NF.6 #3 and #4