The In-Between Game

The In-Between Game
Reporting category
Number and Number Sense
Overview
Students model decimal numbers on grid paper and compare
decimal numbers in the context of a game.
Related Standard of Learning 5.1
Objectives
· Students will use 10 x 10 grids to explore relationships between decimal numbers.
· Students will demonstrate correct ordering of decimal numbers by choosing a number that falls
between two decimal numbers.
Materials needed
· Base-10 Grids, one copy for each student
· In-Between Game, one copy for each pair of students
· Overhead transparency of In-Between Game
· Overhead markers
Instructional activity
1. Initiating Activity: Hand out multiple copies of 10 x 10 grids to each pair of students. Model on the
overhead how to divide the grid into 10 equal-size parts and shade one part. Write this as 1 or 0.1.
10
Ask each pair to similarly shade 2 20
or 0.2 on their first grid. Next, ask them to shade or 0.20 on
10 100
another grid. Have them compare the two shaded decimal numbers. Ask, Which shaded decimal is
the largest? (They are the same or equivalent.)
2. Have the students use two more grids to shade the decimal numbers 0.3 and 0.34. Ask which is
larger (0.34), and call for responses and reasons. Name the corresponding fractions ( 3 34
and
10 100 ).
Use two more grids to shade in 0.46 and 0.5. Ask which is larger (0.5), and call for explanations.
Make sure that the students understand how to compare decimal numbers by place value, and clear
up any misconceptions.
3. Give each pair a copy of the handout In-Between Game. Explain the rules of the game. (Note: you
may need to model a game first on the overhead to get the students started, answering questions as
you go.)
a. The first player chooses a decimal number and writes it on the first row in the first column.
The second player chooses a second decimal different from the first (smaller or larger) and
writes it on the first row in the third column directly across from the first number. Example:
0.5 0.7

. The first player then chooses a decimal number that is in between the original two numbers,
records this number on the second row in the middle column, and crosses out the smallest
(first) number. Example:
0.5 0.7
0.68
c. The first player now writes the two remaining numbers on the third row in the first and third
columns, and the game continues. Example:
0.5 0.7
0.68
0.68 0.7
d. The second player now chooses a number in between these numbers, and so on for five to ten
rounds. Example:
0.5 0.7
0.68
0.68 0.7
0.689
0.689 0.7
4. After the students have had the opportunity to play the game on their own, ask several of the pairs to
display their games on the overhead for all to see and to share their game plays and strategies. When
they display their last round of numbers, have students use the symbols > and < to represent the
inequality.
Follow-up/extension
· As an alternative, this game could be played using fractions, percents, or a combination of fractions,
decimals, and percents.
Sample resources
http://standards.nctm.org/document/chapter5/numb.htm#bp3 . NCTM Principals and Standards for School
Mathematics chapter on the Number and Operations Standard for Grades 35.
http://askeric.org/cgi-bin/printlessons.cgi/Virtual/Lessons/Mathematics/Number_Sense/NUS0200.html
an activity in which students arrange themselves into decimal numbers.
www.funbrain.com Power Football Students score field goals with decimal numbers. Addition,
subtraction, multiplication, and division are covered as well as algebra concepts.
www.aaamath.com/B/grade5.htm This Web site contains reference information and activities for all
fifth grade math topics.
www.matti.usu.edu This Web site contains a library of virtual manipulatives.

The In-Between Game
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Base-10 Grids