April 28

• Warmup: 
• Devil offers a deal: each time you clap, your amount of money doubles, - but you'll pay me $64. You agree, but after 3 claps all you had is gone! How much you started with? How much you need to start to grow richer and richer?
• Find a number consisting only of 1 and 0's which is divisible by 3. By 9. 
• What about numbers made of 8 and 5's?
• What about divisibility by 7? 1001. Remainders.
• Binary numbers: weights 1,2,4,8 etc: represent 1, 5, 14, 17... Adding numbers. Subtracting.
• More shear transformations. What transformations preserve shape?