M4.4.2 For the adult
Translations and combined moves
A shape slides 3 squares right and 2 squares up. How do I write that move with numbers?
What this chapter teaches
A translation slides every point of a shape the same way. A column vector writes the slide: the top number is the move right and the bottom number is the move up. Two slides in a row add, top to top and bottom to bottom.
Three questions to ask
There is no one right wording. Listen for the idea.
- What does the top number of a column vector tell you, and what does a minus sign mean there?
- How do you find the vector when you know a corner and its image?
- Why can two translations in a row always be replaced by one?
After the chapter, the learner can
- Translate a shape by a column vector
- Describe a translation as a column vector
- Find one move that does the same as two moves
What they copy into their notebook
A translation slides a shape. The column vector has the move right on top and the move up below. To combine two moves, add the tops and add the bottoms.