Expressing Tenths Using Decimal Notation
Introducing Decimal Notation for Tenths
Materials
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•
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overhead transparency of Shaded Fraction Strips (template attached)
overhead projector
overhead marker
Activity
Display the first fraction strip example shown on the overhead transparency.
Establish that the strip is divided into ten equal parts and that each part is a tenth of the
whole.
Have students identify the shaded part of the fraction strip.
Six tenths of the strip are shaded.
Use an overhead marker to record “0.6” below the first fraction strip. Emphasize the following
ideas:
– The decimal point separates the whole number part from the fractional part of the
number.
– If there are no wholes, 0 is recorded to the left of the decimal point.
– The decimal number is read in the same way as it was named orally (0.6 is read as “six
tenths” rather than “zero point six”).
0.6
The whole number part
is recorded to the left of
the decimal point.
The fractional part is
recorded to the right of
the decimal point.
The decimal point
separates the whole
number part from the
fractional part.
Decimal Numbers – Grade 4 to Grade 6
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Expressing Tenths Using Decimal Notation
Work through the other fraction strip examples shown on the overhead transparency. For
each strip, have students identify the tenths orally and then invite a student to record the
decimal number.
Emphasize the decimal notation for numbers with whole and fractional parts.
“two and eight tenths”
2.8
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Expressing Tenths Using Decimal Notation
Counting Tenths with a Calculator
Note: Check that the calculators have the memory feature required for this activity.
Enter 0 +0.1 and then press the = key repeatedly. The display should show 0.2, 0.3, 0.4, …
Materials
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calculators – 1 per student
overhead projector
2 fraction circles, cut into tenths (template attached)
Activity
On the overhead projector, assemble a circle using the fraction pieces (tenths). Establish that
the entire circle is “the whole,” that each circle is composed of 10 equal parts, and that each
part is a tenth of the circle.
Next, explain to the students that they will use their calculators to count tenths. Instruct them
to enter 0 + 0.1 on their calculators and ask them to read the display (“one tenth”). Display
one fraction piece on the overhead projector and discuss the connection between it and the
decimal number on the calculator (both represent one tenth).
Add fraction pieces, one by one, to the overhead display. Have students press the = key each
time an additional tenth piece is added. After each addition, have students identify the number
of tenths on the overhead projector and ask them to read the decimal number on their
calculators.
When 10 tenths are displayed on the overhead, have students predict what their calculators
will show before they press the = key. (Some students may predict that the calculators will
show 0.10.) Have students check their predictions by pressing =, and discuss how 1.0
represents one whole (10 tenths).
Continue to add fraction pieces to the overhead display. Have students count beyond one
whole orally (one and one tenth, one and two tenths, one and three tenths, …) and on their
calculators (1.1, 1.2, 1.3, …). When students reach 1.9, have them predict the next number
before continuing to count (and ask them why they predicted that, or ask “how do you
know?”).
Decimal Numbers – Grade 4 to Grade 6
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© Queen's Printer for Ontario, 2006
Expressing Tenths Using Decimal Notation
Decimal Number Grab
Materials
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containers with 9 tens rods and 9 unit cubes from a set of base-ten blocks – 1
container per group of 3 or 4 students
Activity
Show students a rod from a set of base-ten blocks and explain that in this activity it
represents one whole. Next, show a unit cube. Establish that 10 unit cubes make a rod and
that each unit cube is one-tenth of the rod.
Note: In order to allow for multiple entry points, students should be encouraged to take larger
or smaller numbers of rods and cubes as the teacher models both large and small numbers.
Divide the students into groups of 3 or 4. Give each group a container with tens rods and unit
cubes. Explain the activity:
– Students take turns taking a handful of rods and cubes from the container and
displaying what they got to their group. The materials can be set randomly on a surface
(floor, desktop). Rods and cubes do not need to be separated.
– Each group member counts the number of ones and tenths to determine the decimal
number represented by the base-ten materials, and records the decimal number on a
sheet of paper.
– The student who took the materials from the container selects a group member to read
the number (e.g., “4 and 8 tenths,” not “four point eight”). Group members compare
their recorded numbers and help anyone who has written the number incorrectly.
Observe students as they do the activity to assess how well they read and record decimal
numbers. Alternatively, have students select one of the numbers they have created and
explain how they know their answer is right.
Decimal Numbers – Grade 4 to Grade 6
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Template for Fraction Circle (Tenths)
Decimal Numbers – Grade 4 to Grade 6
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Shaded Fraction Strips
This represents the whole
Decimal Numbers – Grade 4 to Grade 6
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Shaded Fraction Strips
Decimal Numbers – Grade 4 to Grade 6
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© Queen's Printer for Ontario, 2006