Folding for Angles
Students will solve angle addition sentences using a folded paper model.
Introduction (5 minutes)
- Hold the folded paper teacher model up and ask your class to turn to a neighbor and tell them what it reminds them of and why (i.e. typical ideas include "origami" or "paper airplane").
- Call on students to share their ideas with the class.
- Open your model, draw lines along the creases, and announce that the class will be exploring ways to add these angles.
Explicit Instruction/Teacher Modeling (10 minutes)
- Pose the question “What’s an angle?” and allow students to think, pair, and share a definition with their neighbor.
- Allow for a few shared student responses and reveal that an angle is made at the intersection of two lines.
- Explain that angles can be wide (greater than 90 degrees) or narrow (less than 90 degrees). Draw a small angle (~10 degrees) and a bigger angle (~140 degrees). Remind your students that we can measure angles in units called degrees, which are like very, very skinny slices of pizza. Draw a 5-degree angle in a magnified way, demonstrating each degree with the use of a protractor.
- Preview the angle poster, sharing common angle models and amounts for: 0, 45, 90, and 180 degrees.
- Demonstrate how you constructed the paper fold model in three folds and traced indentations.
- Explain the lesson objective is for students to identify and add two angles using their own models.
Guided Practice/Interactive Modeling (10 minutes)
- Demonstrate line tracing: Instruct students to label lines by first turning their paper portrait-wise, with the longest line pointing up, and placing an "A" where all lines intersect. Then, going clockwise, label each line beginning with the longest line, B. Label lines C, D, E, F, G, H, and I.
- Show your class angle labeling with angle BAC and evaluate its measurement with the angle poster. Point out that the middle letter should always be the letter of the vertex. So, in this case, point A will always be the middle letter.
- Give each student a paper and lead them through the three-fold sequence, fold tracing, line labeling, and angle labeling using the angle chart.
- Share with your students that angles can be added by taking the measure of each and then adding their amounts. Demonstrate an addition equation with angle names.
- Instruct students to pair with a neighbor and write an addition sentence of their own, share with whole class, and correct any misconceptions.
- Review the lesson objective: to add angles using their paper construction. Assign students to write five addition sentences on the back of their construction and answer any clarifying questions.
Independent Working Time (15 minutes)
- Pair students, allow for students to work independently, and release them to write their addition sentences.
- Circulate around the class and assist by asking probing questions as needed.
- Students can view the paper hat video listed in resources, make one, and calculate its folded angles.
- Provide copies of the traced teacher model and have students label angle measurements.
- Post angle addition sentence frames on a poster for student reference.
Assessment (5 minutes)
- As you circulate, ask students to share one of their angle addition sentences and explain their reasoning. Check for use of academic language.
Review and Closing (10 minutes)
- Have students display their work on their tables and take a silent "gallery walk" to observe student work. A "gallery walk" is a comprehension strategy where students walk silently to view student work, before sharing out observations.
- Conclude with a connection question: "How do you illustrate a standard unit of measurement?"