Idea 13of 15Builds onTurn it, corner by corner
Undo a move
Which move puts a shape back where it started?
Today you'll discover
- how to undo a turn
- what two half turns make
- how to undo a flip
Think firstAn arrow pointing up
The arrow turns 90° clockwise. Which turn brings it back?
Decide first, then press Next. Compare each result with the faint outline.
Four small grids. The first holds an arrow pointing up with a dot at its turn point. The second shows it turned 90 degrees clockwise, pointing right. The third shows it turned back 90 degrees counter-clockwise, pointing up again, with a faint outline of the right-pointing arrow. The fourth shows two half turns bringing it back to the start.
See the whole ideathe big idea and the key word, in one place
The big idea
Undo a move with its opposite: slide back, turn back the other way, or flip again.
Every move has an undo
Each move has an opposite that puts the shape back.
- Slideslide back
- Turn 90°turn back 90°
- Flipflip again
Key word
- full turn
- turning all the way round, 360°, back to where it started
Ready to use it?
- Find the move that undoes a slide, a flip or a turn.