Maryland Math 6.GR.A.2

6.GR.A.2 is a cluster heading. These are the individual standards under it.

• 6.GR.A.2.a

  By packing prisms with unit cubes and using estimation to show that the volume can be found by multiplying the edge lengths of the prism.

• 6.GR.A.2.b

  Apply the formulas V = lwh and V = B · h (B is the area of the base) to find the volumes of right rectangular prisms with fractional edge lengths in context.

01

What Students Need to Do

Students pack a rectangular prism with small cubes and use the count to find its volume. They estimate the volume, then multiply fractional edge lengths or multiply the base area by the height.

02

What Mastery Looks Like

A student can show that six half-inch cubes fill a 1 1/2 by 1 by 1/2 inch prism. They know each small cube is 1/8 cubic inch, so the prism holds 3/4 cubic inch.

03

Common Misconceptions

Students may count six half-inch cubes and call the volume 6 cubic inches. Some multiply only two edges, finding the base area but not the volume. Others write square inches instead of cubic inches.

04

How to Assess It

Exit ticket: A box measures 1 1/2 by 1 by 1/2 inches. Is its volume more or less than 1 cubic inch? Sketch the half-inch cubes that fill it, then calculate its volume.

1. 01

   Cut half-inch cubes from modeling clay, build a 1 1/2 by 1 by 1/2 inch prism, and compare it with a one-inch cube.

2. 02

   Ask: Why do six half-inch cubes fill the box but give a volume of 3/4 cubic inch, not 6 cubic inches?

3. 03

   Give pairs cards marked 1/2, 3/4, 1, and 1 1/2 inches; deal three dimensions, estimate the volume, then calculate and check.

4. 04

   Measure the inside of a rectangular pencil box to the nearest half inch, then estimate and calculate how many cubic inches it holds.

• 5.GR.C.5.a

  Find the volume of a right rectangular prism with whole-number side lengths by filling it with unit cubes in layers and show that the volume is the same as woul...

• 5.GR.C.5.b

  Apply the formulas V = (l)(w)(h) and V = (B)(h) for rectangular prisms to find volumes of right rectangular prisms with whole-number edge lengths to solve probl...