teaching priority concepts in math: grade 8 tricia profic
TRANSCRIPT
Teaching Priority Concepts in Math: Grade 8
Tricia Profic
State Updates
Module 1 and Module 2 are available on engage for grade 8 Module 1 Link
Module 2 Link
The first quarter to half of the year’s modules are “supposed” to be available at the end of the month
Annotated sample questions from April’s state assessment are posted on engage as well Sample Questions link
Tape Diagrams
• Promote perseverance in reasoning through problems.
• Develop students’ independence in asking themselves: “Can I draw something?”
“What can I label?”
“What do I see?”
“What can I learn from my drawing?”
88 children were in swimming camp. One-third of the boys and three-sevenths of the girls wore goggles. If 34 students wore goggles, how many girls wore goggles?
Opening Exercise:
88 children were in swimming camp. One-third of the boys and three-sevenths of the girls wore goggles. If 34 students wore goggles, how many girls wore goggles?
88
34
20
Boys Girls
Wore goggles
Children at swim camp
Did not wear goggles
54
34
Wore goggles
14
94 children are in a reading club. One-third of the boys and three-sevenths of the girls prefer fiction. If 36 students prefer fiction, how many girls prefer fiction?
Try to use tape diagrams to answer the following question:
94 children are in a reading club. One-third of the boys and three-sevenths of the girls prefer fiction. If 36 students prefer fiction, how many girls prefer fiction?
Let’s practice with tape diagrams
Two pears and a pineapple cost $2. Two pears and three pineapples cost $4.50. Find the cost of a pineapple.
Example 2
Henry bought 280 blue and red paper cups. He used 1/3 of the blue ones and 1/2 of the red ones at a party. If he had an equal number of blue cups and red cups left, how many cups did he use altogether?
Example 3
Sana and Amy collect bottle caps. The ratio of the number of bottle caps Sana has to the number Amy has is 2:3. The ratio became 5:6 when Sana added 8 more bottle caps to her collection. How many bottle caps does Amy have?
Example 4
The ratio of songs on Jessa’s phone to songs on Tessie’s phone is 2 to 3. Tessie deletes half of her songs and now has 60 fewer songs than Jessa. How many songs does Jessa have?
Congruence and Rigid Motions
How do you define congruence?
Why are we defining congruence in terms of rigid motions? To avoid having to directly measure objects: Can
we really measure with accuracy?
Are opposite sides of a rectangle really congruent?
Translations
How do you define a translation?
Module definition of a translation: A basic rigid motion that moves a figure along a
given vector.
Yes, vectors in 8th grade….
Activity
Draw on paper any shape you would like and a vector
Trace that shape and vector onto your transparency
Slide your transparency moving your point A to end at your point B
visual of a translation
Reflections
How do you define a reflection?
Module definition of a reflection: A basic rigid motion that moves a figure across
a line
Also, if you connect any point to its reflected image, the line of reflection bisects that segment
Activity
Draw on paper any shape you would like and a line you would like reflect your image on
Trace that shape and line of reflection onto your transparency
Flip your transparency over to see how the image was reflected on the line you chose to draw
visual of a reflection
Rotations
How do you define a rotation?
Module definition of a rotation: A basic rigid motion that moves a figure around
a point, d degrees
Activity
Draw on paper any shape and a point you would like to rotate your shape around
Trace that shape and point on your transparency
Turn your transparency counter clockwise around the point you drew, keeping your transparency matched up with your point
Visual of a Counterclockwise Rotation
Sequencing Rigid Motions
Congruence of Figures using Rigid motions
Congruence of Angles
How to prove the congruence of angles when you have parallel lines cut by a transversal using rigid motions.
Proving the angle sum of the interior angles of a triangle is 180 degrees given known facts about straight angles and the relationships between angles with parallel lines cut by a transversal.
Today’s Task
Each pair will be given a lesson from Grade 8 Module 2 to analyze
We know that some of these lessons will need modifications to reasonably teach these concepts
Please fill out the lesson plan form
If you modify any of the class problem sets or homework assignments, please add them to the lesson plan word document
After building your lessons, we will regroup and modify the mid-module and end-of-module assessments to add multiple choice questions