Learning Targets
Tape diagrams are useful for representing how quantities are related and can help us answer questions about a situation.
Suppose a school receives 46 copies of a popular book. The library takes 26 copies and the remainder are split evenly among 4 teachers. How many books does each teacher receive? This situation involves 4 equal parts and one other part. We can represent the situation with a rectangle labeled 26 (books given to the library) along with 4 equal-sized parts (books split among 4 teachers). We label the total, 46, to show how many the rectangle represents in all. We use a letter to show the unknown amount, which represents the number of books each teacher receives. Using the same letter, , means that the same number is represented four times.
Some situations have parts that are all equal, but each part has been increased from an original amount:
A company manufactures a special type of sensor, and packs them in boxes of 4 for shipment. Then a new design increases the weight of each sensor by 9 grams. The new package of 4 sensors weighs 76 grams. How much did each sensor weigh originally?
We can describe this situation with a rectangle representing a total of 76 split into 4 equal parts. Each part shows that the new weight, x + 9, is 9 more than the original weight,x .
Here are three stories with a diagram that represents it. Explain why the diagram represents the story. Find any unknown amounts in the story.
Here are three more stories. Draw a tape diagram to represent each story. Then describe how you would find any unknown amounts in the stories.
This summary video is joined with 6.3 Reasoning about Tape Diagrams (Part 2).