Multiplying multidigit whole numbers
by fractions
September 22, 2014
Multiplication Quiz
• This is an independent assignment. When you are
finished turn in your paper and wait for further
instructions.
• You will have 20 minutes. Do your best and
remember, SHOW YOUR WORK!
•
Mathematical Practices:
•
Practice 1: Make sense of problems and persevere in solving them
•
Practice 2: Reason abstractly and quantitatively
•
Practice 4: Model with Mathematics
Multiply then divide
by the same number
• 3x2=
• 3x2x10÷10=
Multiply then divide
by the same number
• 5x .3=
• 5x.3x10÷10=
Multiply then divide
by the same number
• 3 x 2.5=
• 3 x 2.5 x 10÷10=
Mathematical Practices:
Practice 6: Attend to Precision
Practice 1: Make sense of problems and persevere in solving them
Practice 2: Reason abstractly and quantitatively
Practice 8: Look for and express regularity in repeated reasoning
Decompose Decimals
7.463
How can this number be broken into two
different units?
Can it be done more than one way?
Can you use a picture?
Mathematical Practices:
1. Make sense of problems and persevere in solving them
3. Construct viable arguments and critique the reasoning of others
4. Model with mathematics
5. Use appropriate tools strategically
Word Problem of the
Day!
• The fifth grade craft club is making aprons to
sell. Each apron takes 1.25 yards of fabric that
costs $3 per yard and 4.5 yards of trim that costs
$2 per yard. What does it cost the club to make
one apron? If the club wants to make $1.75
profit on each apron, how much should they
charge per apron?
Multi-digit Multiplication
and decimals
43 x 2.4
Round the factors to estimate:
Find the actual product:
Use an area model and solve using the standard algorithm
3.5 x 42
Area model and standard algorithm
15.6 x 73
Area model and the standard algorithm
Mathematical Practices:
1. Make sense of problems and persevere in solving them
2. Reason abstractly and quantitatively
3. Construct viable arguments and critique the reasoning of others
4. Model with mathematics
5. Attend to precision
Problem Set
• This is independent work. If you are confident please
move your number to “Willing to Help”
• If you need help you may ask one of these students.
• Remember your accountable talk, do not give answers
to your classmates, rather help them understand what
you are doing.
• I will call back small groups
Exit ticket
• Find the Product using the Standard Algorithm and an area
model
33.2x 21=
1.7X55=
If the product of 485x 35 is 16,975, what is
the product of 485 x 3.5? How do you know?