standard_description: Rewrite simple rational expressions in different forms; write a(x)/b(x) in the form q(x) + r(x)/b(x), where a(x), b(x), q(x), and r(x) are polynomials with the degree of r(x) less than the degree of b(x), using inspection, long division, or, for the more complicated examples, a computer algebra system.
problem_activity: Narrative
The purpose of this Number Talk is for students to demonstrate strategies and understandings they have for dividing a three-digit number by a two-digit number. These understandings help students develop fluency and will be helpful later in this lesson when students use an algorithm that uses partial quotients to divide larger three-digit numbers by two-digit numbers.
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.
\(110 \div 10\)
\(121 \div 11\)
\(132 \div 12\)
\(154 \div 14\)
Student Response
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Activity Synthesis
“What stays the same with each problem? What changes?” (The quotient is always 11. There are always 11 groups of the divisor. The dividend and the divisor change.)


aligns: no