April 21

• Warmup: 
• Adding 0 makes 2-digit number 252 bigger, - find the number
• Adding 0 between 2 digits makes it 9 times bigger
• Moving 9 from 1st to last (3rd) place increases the number by 216
• Number trick:
  x-> 3x-> 30x-> 30x-5-> 6x-1->6x+12->x+2->2 
• Design your own trick
• Coordinate system: shears
  S:(x,y)->(x+y,y) 
• Apply to squares and rectangles.
• U:(x,y)->(x,y-x).
• Find SU. Find SU^6.
• Game: card guessing?