standard_description: Explain why a fraction a/b is equivalent to a fraction (n × a)/(n × b) by using visual fraction models, with attention to how the number and size of the parts differ even though the two fractions themselves are the same size. Use this principle to recognize and generate equivalent fractions.
Grade 4 expectations in this domain are limited to fractions with denominators 2, 3, 4, 5, 6, 8, 10, 12, and 100.
problem_activity: Narrative
The purpose of this Number Talk is to elicit strategies and understandings students have for addition and subtraction with 3 and 5. These understandings help students develop fluency and will be helpful later in this lesson when students will need to be able to create a yardstick with just the numbers 3 and 5.
Launch
Display one expression.
“Give me a signal when you have an answer and can explain how you got it.”
1 minute: quiet think time
Activity
Record answers and strategy.
Keep expressions and work displayed.
Repeat with each expression.
Student Facing
Find the value of each expression mentally.
\(3 + 5\)
\(5 - 3\)
\(5 - 3 + 5\)
\(3 + 5 + 3 + 3\)
Student Response
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Activity Synthesis
“What other numbers can we make with 3 and 5? Think of two other numbers you can make. You can use as many threes and fives as you like and you may subtract and add.”


aligns: no