Lesson plan Grade 3 Math
Cranemont Storm Drain Screens: A Grade 3 Picture Graph Lesson
A 45-minute grade 3 lesson where students read and build a scaled picture graph with a key of 5 from litter counts pulled off storm drain screens in a fictional town.
Objectives
- Students will read a scaled picture graph in which one symbol stands for 5 pieces of litter.
- Students will answer how-many-more and how-many-in-all questions from a scaled picture graph.
- Students will draw the correct number of symbols to add a new category to a scaled picture graph.
Vocabulary
- Storm drain
- A storm drain is the grate at the edge of a street that swallows rainwater and sends it through pipes to the nearest creek or river. That water is usually not treated, so only rain belongs down the drain.
Also: picture graph, key, symbol, litter
Teacher overview
Storm drains carry rain off streets, and many towns put metal screens over the openings so that cups, wrappers, and leaves stay out of the pipe and out of the creek. The town of Cranemont in this lesson is fictional, and the litter counts below were written for the lesson rather than copied from a real cleanup record. Students read a picture graph in which one drop symbol stands for 5 pieces of litter, answer comparison questions from it, and then draw symbols for a fifth street. The misconception this lesson corrects is counting symbols as if each one stood for a single item, which leads a student to report that a street with 9 symbols had 9 pieces of litter.
Procedure
Hook (5 min): Show students two symbols on the board and say that together they stand for 10 pieces of litter. Ask what one symbol must stand for, and how many symbols you would need to show 25 pieces. Take answers without correcting them yet.
Direct instruction (10 min): Introduce the setting: crews in Cranemont pull litter off four storm drain screens every Friday and count what they find. Draw the graph frame on the board with the four street names and the key, "Each symbol stands for 5 pieces of litter," written directly under the title. Fill in Bell Street with 6 symbols and think aloud: 6 groups of 5, so 6 × 5 = 30 pieces. Point out that the key is the only place the number 5 appears, so every reading of the graph has to pass through it.
Guided practice (12 min): Students complete handout items 1 and 2 with a partner while you fill in the remaining three streets on the board graph. Then ask the class item 3 as a whole-group check. This is the formative check: hold up fingers for the number of symbols, then write the number of pieces on the handout and hold it up, and confirm that at least four out of five students show a different count for the two questions rather than the same one.
Independent practice (13 min): Students complete handout items 4 through 6 on their own, using grid paper to draw the new street's symbols for item 6. Circulate and ask any student who draws 25 symbols to reread the key aloud.
Closure (5 min): Collect the handouts and post the four street totals on chart paper. Ask one closing question aloud: if the crew wanted the graph to use a key of 10 instead of 5, would Oak Lane need more symbols or fewer? Take two answers and leave the chart posted for the next lesson.
Student Handout
Crews in Cranemont pull litter off four storm drain screens each week. The table shows how many symbols each street has on the picture graph for one week.
Key: each symbol stands for 5 pieces of litter.
| Street | Number of symbols |
|---|---|
| Bell Street | 6 |
| Miller Road | 4 |
| Oak Lane | 9 |
| Pine Way | 3 |
- How many pieces of litter came off the Bell Street screen?
- How many pieces of litter came off the Oak Lane screen?
- How many more pieces of litter came off Oak Lane than off Pine Way?
- How many pieces of litter came off Miller Road and Pine Way together?
- How many pieces of litter came off all four screens in all?
- Next week a crew finds 25 pieces of litter on Reed Street. How many symbols would you draw for Reed Street?
From Water for Schools (waterforschools.org). This material is in the public domain (CC0) and may be copied, edited, and shared freely.
Answer Key
- Answer: 30 pieces.
Bell Street has 6 symbols, and each symbol stands for 5 pieces, so 6 × 5 = 30 pieces. - Answer: 45 pieces.
Oak Lane has 9 symbols, so 9 × 5 = 45 pieces. - Answer: 30 pieces.
Oak Lane has 45 pieces and Pine Way has 3 × 5 = 15 pieces, so 45 − 15 = 30 more pieces. - Answer: 35 pieces.
Miller Road has 4 × 5 = 20 pieces and Pine Way has 15 pieces, so 20 + 15 = 35 pieces. - Answer: 110 pieces.
The four totals are 30, 20, 45, and 15 pieces, and 30 + 20 + 45 + 15 = 110 pieces. - Answer: 5 symbols.
Each symbol stands for 5 pieces, and 25 ÷ 5 = 5, so Reed Street needs 5 symbols.
Differentiation
Support
Give students a version of the graph with the symbols already drawn as small circles in rows, so they can count in fives by touching each circle. Provide a skip-counting strip that reads 5, 10, 15, 20, 25, 30, 35, 40, 45 along the top of the page. Let students answer items 1 and 2 before attempting any comparison item.
Extension
Ask students to redraw the same four streets using a key of 10 pieces per symbol, including half symbols where needed, and explain which key makes the graph easier to read and why. Have them write one new question about the graph that requires two steps to answer, and swap it with a partner.
ELL supports
Pre-teach "storm drain," "screen," "litter," and "key" with a labeled sketch of a curb, a grate, and the pipe below it. Point to the word "key" on the graph each time it is used, and provide the sentence frame "Each symbol stands for ___ pieces, so ___ symbols means ___ pieces." Allow students to answer item 6 by drawing rather than writing.