Purpose: To form a number line with decimals and mixed decimals

Materials: Master #12 "Decimal Number Line" and Master #13 "Bars for Decimals" (both attached)

copies Master #13

pencils and paper copies of Master #12 Transp #4

Activity 1 Fractions and decimals for tenths

Student copies of these bars can be cut from Master #13.

What is the fraction for each bar? As you receive each name, write its fraction to the left of the bar.

What is the decimal for each bar? As you write the decimals to the right of the bars, repeat the two forms of their names: "point one" or "one-tenth"; "point three" or "three-tenths", etc. Describe the bars for each of the following decimals and complete each

equation by writing the equal fraction.

.7 = 710

.2 =

.6 =

.5 =

.8 =

.4 =

Activity 2 Forming a number line from 0 to 1 with decimals

1. Student will need pencils and the Master #12 "Decimal Number Line" on page 124.

What do you notice about your number line? (It has the numbers 0, 1.0 and 2.0. It has 10 spaces between these numbers.)

You can think of this line between 0 and 1 as a thin bar with 10 equal parts. Instead of shading the parts, we will write decimals beneath the marks on the line.

2. Show students the Decimal Number Line, and above this place a white tenths bar with 3 shaded parts as shown here.

What decimal should we write below the line for this bar? (.3) As you write .3 on your copy of the number line, ask students to write this decimal on their lines.

FRACTIONS - DECIMALS - PERCENTS 4.NF.6 Step 3 Number Lines with Decimals and Mixed Decimals

TEACHER MODELING/STUDENT COMMUNICATION

Master #12 Transp #4

Where should the decimals for the 1/10 bar and the 9/10 bar be written? (Below

the marks just after "0" and just before "1.0".) Write the decimals on your line for the remaining marks between 0 and 1.0. Why is the number "1.0" on the line? (For a whole bar, 1.0 is used for decimals

to show one whole bar and zero tenths.) Place the whole bar for tenths beneath the line between 0 and 1.0 and leave it there for the next activity. Activity 3 Extending the line from 1.0 to 2.0 for two whole bars

Place the tenths bar for .4 above the line between 1.0 and 2.0 and ask:

What decimal should be written below this bar? (1.4 for one whole bar and .4 of a bar.) Write this decimal on your line and ask students to write it on their lines.

We call this number "one and four-tenths" or "one point four". This type of number is a mixture of two types of numbers: the whole number

1 and the decimal .4, so we call it a mixed decimal. If this bar is replaced by a bar with 9 out of 10 parts shaded, what decimal

should be written on the line? (1.9 below the mark just before 2.0) Illustrate this by placing the bar for .9 above the line.

Write the decimals for the remaining marks between 1.0 and 2.0 on your lines. Why is the number 2.0 written on the number line? (It represents 2 whole bars

and zero tenths.) You have formed the beginning of a number line. How far do you think a

number line could be extended? (To any number, that is, indefinitely.) Discuss this idea and point out that number lines theoretically extend without end.

Worksheets 100-101 from Fraction Bars Teacher Resource Pack (Grades 5-8) decimalsquares.com Decimal Darts (Typing mixed decimals to aim darts at balloons)

INDEPENDENT PRACTICE and ASSESSMENT

Bars for Decimals

Master #13 - Grades 5-8 Fractions - Decimals - Percents, Step 3