october 12

Write numbers 1...9 so that any two neighbors were at most 2 apart and 9 is in the middle.

Diza has in her box red, blue and green socks. She never puts on socks of the same color. How many ways are there for her to choose her socks? If she has B, R, G and Y?

Envelopes for the cube

Envelopes for the tetrahedron...

Midpoints of vectors...

hopscotch! making the cupcake fly. Did not do today: vectors won.

Homework

1. In a box there are 5 pencils, Red, Blue, Green, Yellow and Orange. Joan wants to choose three of them. How ways are there to choose them?

2.

Mark on graph paper three vectors:

• A(3,3);
• B(-3,1)
• C(1,-3)

Draw the midpoints between A and B, B and C, C and A.