Answer key · Set B
Third-Unit and Half-Foot Cubes
127 3 cubes across, 3 deep and 3 high: 3 × 3 × 3 = 27.
218 3 × 3 = 9 in a layer, and 2 layers: 18.
39/4 18 cubes shared 8 to a cubic foot is 18 ÷ 8 = 18/8, which is 9/4, or 2 and a quarter.
4True 1/2 × 1/2 × 1/2 = 1/8. Eight of them fill one cubic foot.
55/3 5 × 3 × 3 = 45 cubes. 45 cubes shared 27 to a cubic unit is 45/27, which is 5/3.
6Box 3 8 half-unit cubes fill 1 cubic unit, so 2 cubic units need 16 cubes. Box 3 has 2 × 4 × 2 = 16. Box 1 has 12 and Box 2 has 24.
71-C, 2-A, 3-D, 4-B Across × deep × high: 5 × 5 × 5, 6 × 6 × 6, 8 × 8 × 8 and 10 × 10 × 10.
86/5 1/2 × 3/5 = 3/10, and 3/10 × 4 = 12/10, which is 6/5.
9True The volume is length × width × height, whether the edges are whole numbers or fractions.
105 cubic inches 40 cubes shared 8 to a cubic inch is 40 ÷ 8 = 5.
112, 3, 1, 4 The volumes are 1/2, 3/4, 1 and 3/2.
123/2 6 × 4 × 4 = 96 cubes. 96 cubes shared 64 to a cubic unit is 96/64, which is 3/2.
13Your own words: a grown-up reads it.
Mark each answer, count the right ones and write the score on the sheet.