Answer key · Set C
Fraction Edges and Joined Boxes
1120 6 × 4 = 24 in a layer, and 5 layers: 24 × 5 = 120.
215 cubic inches 120 cubes shared 8 to a cubic inch is 120 ÷ 8 = 15.
33 3 × 2 × 4 = 24 cubes, and 8 of them make a cubic foot: 24 ÷ 8 = 3. Or 3/2 × 1 × 2 = 3.
4Box 3 Count the cubes. Box 1 has 4 × 3 × 3 = 36, Box 2 has 6 × 2 × 3 = 36 and Box 3 has 3 × 3 × 5 = 45, the most.
51 2 1/2 is 5/2. Then 5/2 × 2 = 5, and 5 × 1/5 = 1.
66 cubic feet Volume is base × height: 3/4 × 8 = 24/4 = 6 cubic feet.
71/2 Volume is base × height: 5/6 × 3/5 = 15/30, which is 1/2.
8False 4 × 4 × 4 = 64 quarter-unit cubes fill 1 cubic unit, so each is 1/64. Also 1/4 × 1/4 × 1/4 = 1/64.
9Because 2 × 2 × 2 = 8: 2 across, 2 deep and 2 high. There are 2 layers of 4 cubes. The height counts too.
101-C, 2-A, 3-B, 4-D Multiply the three edges: 1/8, 1/2, 2 and 3/4.
115/2 3 × 2 × 2 = 12 cubes and 2 × 2 × 2 = 8 cubes make 20 cubes. 20 ÷ 8 = 20/8, which is 5/2.
12False Both ways find the same volume. Counting 12 half-unit cubes is 12/8 = 3/2, and 1 × 3/2 × 1 = 3/2.
13Your own words: a grown-up reads it.
Mark each answer, count the right ones and write the score on the sheet.