standard_description: Compose two-dimensional shapes (rectangles, squares, trapezoids, triangles, half-circles, and quarter-circles) or three-dimensional shapes (cubes, right rectangular prisms, right circular cones, and right circular cylinders) to create a composite shape, and compose new shapes from the composite shape. (Students do not need to learn formal names such as “right rectangular prism.”)
problem_activity: Task
2 bottles of water cost $5.00.
Fill in the table that shows the costs for 4, 6, and 8 bottles. Find the cost for a single bottle in each case.
| Number of bottles | Cost (\$) | Cost per bottle |
|-------------------|-----------|-----------------|
|       $$2$$       |   $$5$$   |                 |
|       $$4$$       |           |                 |
|       $$6$$       |           |                 |
|       $$8$$       |           |                 |
5 granola bars cost $4.00
Fill in the table that shows the costs for 10, 15, and 20 granola bars. Find the cost for a single granola bar in each case.
| Number of granola bars | Cost (\$) | Cost per bar |
|------------------------|-----------|--------------|
|         $$5$$          |   $$4$$   |              |
|         $$10$$         |           |              |
|         $$15$$         |           |              |
|         $$20$$         |           |              |
Explain why if you can buy $a$ items for $b$ dollars, or buy $2a$ items for $2b$ dollars, the cost per item is the same in either case.


aligns: no