standard_description: Use a pair of perpendicular number lines, called axes, to define a coordinate system, with the intersection of the lines (the origin) arranged to coincide with the 0 on each line and a given point in the plane located by using an ordered pair of numbers, called its coordinates. Understand that the first number indicates how far to travel from the origin in the direction of one axis, and the second number indicates how far to travel in the direction of the second axis, with the convention that the names of the two axes and the coordinates correspond (e.g., x-axis and x-coordinate, y-axis and y-coordinate).
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
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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