Topic: “Seeing” and counting 3D cubes

Today we learned how to “see” and count 3D cubes.

• Visualize the 3D cubes in your brain
• Know there are hidden parts (blocked from view)
• Get help from the visible part to learn about the hidden part (e.g. using symmetry)

Homework

Note: homework are due next week. We will check it at the beginning of the next class.

1. Amy wants to build a big cube from small ones, so that the edge of the big cube is made up from 3 small cubes. When she takes a break, she has completed the following part using 7 small cubes. How many more small cubes will she still needs to complete the big cube?

2. 3 mini rubic cubes (each of them is 2x2x2) are connected one after another in the following picture. Some parts of them overlap each other. Can you tell altogether how many small cubes are there?