0.75 3.75 18.75 93.75 468.75 1. 2000.75 4. 2635.75 18. 3. 2500.75 2. 2343.75 5. 2812,75 1/2 2 7/2 5 1. 9/2 4. 15/2 19. 2. 11/2 5. 17/2 3. 13/2 16 61 1. 43 4. 32 20. 1 76 67 82 28 3. 39 2. 41 5. 30

How many numbers have digits which are all ”1”s and ”2”s, and thedigits add up to 8? A few such numbers are 12212, 112121, and 112121. (HINT: breakthe list into cases and count each one. You can count them by hand, but you will savea lot of time if you apply the right formula.)

Find the smallest positive integer N that satisifies all of the following conditions N is a square N is a cube N is an odd number N is divisible by twelve different prime numbers   How many digits does this number have ?

(9) How many different two-digit numbers can be made from the digits 3, 5 and 7 if: (a) the digits can be repeated? (b) the digits cannot be repeated? List all possibilities in each case.