Introduction to Decimals
Using Base 10 Blocks
Materials Needed:
*Base 10 Blocks- either homemade or
bought commercially
*page protector sheets with a blank
sheet of copy paper (this is to be used as
their "personal white board")
*dry erase markers
*paper towels for "erasers"
This is the first of a unit that teaches decimals, fractions, and percents. The end result of the
total unit, will be for students to be able to easily convert between the three different forms of
numbers. I understand that not all grade levels must go that far. I will have each piece of the
unit seperately, and then one large packet that includes all of the pieces in one place. I have
taught from 6th grade to 9th grade and I've taught many different types of students, including
English language learners. I have found that if students have a deep understanding of number
sense, the rest comes much easier. This is my attempt at helping teachers to learn to build that
number sense with their own students.
Putting students in groups or having them perform this independently is purely up to you and
the level at which your students are at. You could look at it different ways. In cooperative
learning groups, students are able to work off one another, but they aren't all getting that
"hands-on" approach as much as working independently. Working independently, they are
getting the sole role of using the hands-on materials, but they aren't getting the help from other
students. I think often, teachers understand their students and it would be better for you to
make that call.
The "personal white boards" are just an added something that students find entertaining and
engages them. Most of the things in this activity are not necessarily things that you want to
be turned in to be graded, but you want students to write down so that you can check for
understanding by walking around the room.
The best thing is to have the plastic commercially made base 10 blocks, but I understand
budgets. That is why I made these templates. You can print them on colored paper, laminate
them and then cut them out. I place mine in ziplock baggies to make it easier to keep.
Base 10 Blocks
Printables
Cut these apart to make the
small unit squares
Introduction of Decimals
Help students
understand that this is
called a flat and is
worth one whole.
This figure is called a rod
and is worth one-tenth or
0.1. It is called one-tenth,
because it is one out of ten
that make up one whole.
This is called one unit and
is worth one-hundredth or
0.01. It is called onehundredth, because it is
one out of one hundred
that make up one whole.
Students need to understand the decimal side of place value. Spend a little bit writing on your
white board or chalk board about place value.
hundreds
tens
ones
tenths
hundredths
thousandths
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After explaining the basics of base 10 blocks, ask students to model 1.23 with their
blocks. Let the students try for a little while before offering any help. This is where the
whole "discovery learning" takes place. Students love to try to figure things out, especially
when they have hands-on manipulatives to work with. Walk around the room and make
sure that the students are modeling the number correctly. Model the number yourself just
to make sure everyone has the same thing. The model should have one flat, two rods, and
three units. Have them do this with a couple of more numbers until you are sure everyone
is understanding. Even if some of the students understand, they still like playing with the
manipulatives and won't mind doing a couple of extras. Here are some examples you could
use. Do these numbers one at a time and stop after each one to make sure everyone
knows how to do it.
1. 2.47
2. 3.39
3. 1.4
4. 2.7
Now ask students to put the blocks aside for a second and to get out their "personal
white boards." Have them model some numbers by drawing them on these white boards.
Here are some examples to use. They can just draw generic pictures of the figures, we
aren't in art and our focus is not on how pretty, but whether they understand the
concept we are learning. To draw a flat, just a large square is sufficient. To draw a rod, a
long, skinny rectangle is fine. To draw a unit, a small square is great. It is not necessary
to put in all of the little squares in the flats or rods.
1. 2.77
2. 5.07
3. 7.5
4. 8.6
Now you can draw a couple of pictures of models, and have them write the numbers.
By this time, your students should be comfortable with the concept of decimals.
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Modeling Decimals
Fill out the following picture with the proper place value names.
Draw a model of the decimal
number 3.89.
Draw a model of the decimal
number 4.06.
Write the decimal number of
the following model.
Write the decimal number of
the following model.
Modeling Decimals
Fill out the following picture with the proper place value names.
hundreds
tens
ones
tenths
hundredths thousandths
Draw a model of the decimal
number 3.89.
Draw a model of the decimal
number 4.06.
Write the decimal number of
the following model.
Write the decimal number of
the following model.
3.35
2.52
For the Love of Teaching Math
For more great activities like the one you just
purchased, please visit my blog at
www.fortheloveofteachingmath.com or visit my store at
http://www.teacherspayteachers.com/Store/Andrea-Kerr
www.fortheloveofteachingmath.com