BASE TEN BLOCKS
QUESTION
QUESTION
5
How many different ways
can you show 21?
Use your Base Ten Blocks. How many different
ways can you show 21? Make a recording of all the
ways you can show 21. Tell how you know each way
shows 21.
MATERIALS
For each pair of students
Base Ten Blocks (2 tens, 21 ones)
paper and pencils for recording
For the overhead projector
Base Ten Blocks (1 ten, 14 ones)
18
• MHR
QUESTION 5
INTRODUCING THE QUESTION
1
On the overhead projector write the numeral 13. Can you show
this number with your Base Ten Blocks? How did you do it?
As students explain, put blocks on the projector to show 13. Are
there other ways to use blocks to show 13? Tell us.
2
Tell students that their challenge is to use their Base Ten Blocks to
find different ways to show 21. Work with your partner to
show 21 with the Base Ten Blocks. How many different ways
can you show 21? Make a recording of all the ways you can
show 21.Tell how you know each way shows 21.
WHAT SHOULD YOU DO IF . . .
en Blocks or do
T
e
as
B
d
se
u
r
neve
they
If students have
of place value,
g
in
d
n
ta
e
rs
e
av
h
d
n
ts
u
uden
s.
not have a clear
Some st g star ted?
o with the block
d
to
at
h
w
f
o
to the blocks
difficulty gettin
may be unsure
re
su
o
p
x
e
re
o
eed m
on a
Students may n
rtable working
fo
m
co
l
e
fe
y
e
before th
lem.
structured prob
with
to represent 21
s
ay
w
le
ib
ss
o
p
three
mber
ave a strong nu
ly? There are
h
ar
ts
e
n
h
e
is
d
u
fin
st
ts
If
n
s.
e
ud
Challenge these
Base Ten Block
y.
kl
ic
Some st
u
q
h
is
fin
likely
e more
sense, they will
umbers that hav
n
r
e
rg
la
h
it
w
students
es.
possible outcom
at they
n’t convinced th
e
ar
ly
ab
b
ro
p
dents
erience
nd These stu
tions. With exp
u
lu
fo
so
e
le
av
h
ib
ss
ts
m
o
n
p
e
l
d
al
u
r now allow the
Fo
.
Some st to show 21 but have found
ce
n
e
fid
n
co
ore
have
all three ways
they will gain m
el certain they
fe
y
s?
e
ay
th
l
w
ti
r
n
e
u
th
g
o
n
r
ki
keep looking fo
to continue loo
erent ways.
iff
found all the d
QUESTION 5
MHR •
19
WHAT YOU MIGHT SEE
2 tens
1 one
1 ten
11 ones
21 ones
Some students may find all three ways to show 21
with the Base Ten Blocks.
1 ten
21 ones
Some students may use too many blocks. They may
have focused on adding more ones blocks without
removing a tens block.
WHAT TO LOOK FOR IN A STUDENT’S WORK
Was the student able to show 21 in three different ways?
Does the student’s recording clearly describe how each way shows 21?
20
• MHR
QUESTION 5
QUESTIONS FOR DISCUSSION
How many ways did you find to show 21? What were those ways?
How did you know that you had found all the ways to show 21?
Which way used the fewest blocks? Which way used the most
blocks?
How did you organize your work?
JOURNAL REFLECTION
Do you think there would be more or fewer ways
to show 29 than there were to show 21? Explain.
Show a friend what 21 means.
EXTENSION
You can extend the lesson by asking students related questions.
What are the possible values? I have three Base Ten Blocks.
They are either tens or ones blocks. Use your Base Ten Blocks to
find all the values. Record the blocks and their values.Tell how you
know you have found them all.
Can you show 100 in at least three different ways? Use
your ones, tens, and hundreds blocks to show 100 in at least three
different ways. Make a recording of each way.Tell how you know
each way shows 100.
QUESTION 5
MHR •
21