standard_description: Express the length of an object as a whole number of length units, by laying multiple copies of a shorter object (the length unit) end to end; understand that the length measurement of an object is the number of same-size length units that span it with no gaps or overlaps. Limit to contexts where the object being measured is spanned by a whole number of length units with no gaps or overlaps.
problem_activity: Narrative
The purpose of this activity is for students to practice multiplying multi-digit numbers that have one or more digits of 0 at the end. Monitor for students who:
use the standard algorithm to evaluate
\(6,\!700 \times 89\)
.
multiply the product
\(67 \times 89\)
by 10 to find the value of the product
\(670 \times 89\)
.
multiply the product of
\(670 \times 89\)
by 10 to find the value of the product
\(6,\!700 \times 89\)
.
Students who observe that
\(670 = 10 \times 67\)
and
\(6,\!700 = 10 \times 670\)
and use these relationships to find the values of the products are observing regularity in repeated reasoning and using their knowledge of how to multiply a whole number by 10 (MP7, MP8).
Representation: Internalize Comprehension.
Synthesis: Invite students to identify which details were important to find products of multi-digit numbers that have zero digits. Display the sentence frame, “The next time I multiply a number that contains zero digits, I will pay attention to . . . .“
Supports accessibility for: Conceptual Processing, Memory
Launch
Groups of 2
Activity
5–7 minutes: independent work time
5–7 minutes: partner discussion
Student Facing
Find the value of each product.
1.
[IMG]
2.
[IMG]
3.
[IMG]
4.
[IMG]
Student Response
Teachers with a valid work email address can
click here to register or sign in
for free access to Student Response.
Activity Synthesis
Display the product
\(6,\!700 \times 89\)
:
Ask previously identified students to share their solutions.
Display student work or the image from the sample response:
[IMG]
“What is the relationship between
\(670\times89\)
and
\(6,\!700\times89\)
?” (The product
\(6,\!700\times89\)
is ten times larger because one of the factors is ten times greater.)
“What is the relationship between
\(67 \times 89\)
and
\(6,\!700 \times 89\)
?” (The product
\(6,\!700 \times 89\)
is 100 times as large as
\(67 \times 89\)
since 6,700 is
\(100 \times 67\)
.)


aligns: no