Making connections:
Multiplying Decimal Numbers
Recap
Last time we met, you. . .
min
● took a look at the Problem-of-the-Day Protocol
● completed Steps 3, 4, and 5 of the protocol for
Concession Stand Problem
Std: NY-6-NS.3
Fluently add,
subtract,
multiply, and
divide multi-digit
decimals using a
standard
algorithm for
each operation.
● complete steps 1, 2 for a new problem
3
Understanding Decimal Multiplication
Today you will. . .
3
min
● use your understanding of the place-value system
to explain your thinking
Std: NY-6-NS.3
Fluently add,
subtract,
multiply, and
divide multi-digit
decimals using a
standard
algorithm for
each operation.
● make connections between fraction multiplication,
place value and the decimal multiplication
algorithm
● use the decimal multiplication algorithm
The Place Value Mat & Multiplying Fractions
Convert each sentence to decimal representation, what do you notice?
Looking at Patterns and Structure
Convert each sentence to decimal representation, what do you notice?
Making connections:
Multiplying Decimal Numbers
How the algorithm works.
1. Multiply the numbers as if there
were no decimals (similar to multiplying
the numerators of the fraction).
2. Add the # of decimal places in
each of the factors (this is like
multiplying the denominators of the
fractions).
3. Place the decimal in the product
so that the number of decimal
places in the product is the sum of
the decimal places in the factors.
(this is like the final denominator value).
Making connections:
Multiplying Decimal Numbers
Sometimes you may need to
insert zeros in front of the
product so that you have the
right number of decimal places.
Note that you
needed to add two
zeros before 296
to get the 5
decimal places.
Since the ten thousandths
place had a zero, indicating
no value, I can remove the
zero. I can drop the zeros at the
end after placing the decimal
point.
Find the product of 0.4 and 0.17
Independently set up and solve this problem
3
min
Breakout Group - A
(1)
(2)
Set up the problem in your notebook.
Find the product
Show all steps in your work
a) 7 x 0.5
c) 1.9 x 0.46
b) 12 x 0.08
d) 24 x 0.17
15
min
Breakout Group - B
(1)
(2)
Set up the problem in your notebook.
Find the product
Show all steps in your work
15
min
a) Lenny jogged along a trail for 1.35 hours. He
ran at a pace of 3.2 miles per hour. How far did
Lenny jog?
c) Jeff is training for a walkathon. He walked 8.84
miles at an average speed of 3.4 miles per hour.
Then he walked for an additional 1.6 miles at the
same speed. How many hours did Jeff walk in
all?
b) The wings of some hummingbirds beat 52
times per second when hovering. If a
hummingbird hovers for 35.5 seconds, how many
times do its wings beat?
d) Explain why the product of 0.25 and 0.4 has
only one decimal place.
Show what you know
Complete the evidence of learning in Jupiter
Chess Club Sales
To be done independently
You may refer to your notes
You may utilize the manipulatives
4
min