### Monica Capula ## Counting questions and Mathematical Writing #### Five original counting questions 1. How many different ways can you rearrange the work "CAT" Answer:6 How: Summation, writing all combinations, then adding it all up. Equation/Work:CAT,ATC,TAC,CTA,ACT,TCA 2. There are 4 people at a conference and each shakes everyones hands, how many times was each hand shake? Answer:6 How: using the sum principle with diagram. The diagram using vertices as people and edges as handshakes Equation/Work: ![](https://i.imgur.com/7SEb7Z8.jpg) 3. You are asked to flip a coin three times and to record the outcome for each flip. How many possible outcomes are there? Answer: 8 outcomes How: using product principle, there are 3 flips and 2 outcomes.Creating combination and adding them up Equation/Work:HHH,TTT,HHT,TTH,HTH,HTT,THT,THH 4. You play a lottery, you have to choose five number and each number between 1 and 29, inclusive. How many ways can you fill out the lottery card? Answer:362880 How:Using product notation Equation/Work: 20 ∏ k =19x18x17x16x15x14x13x12x11x10x9x8x7x6x5x4x3x2x1=3200000 k=1 5. How many ways can 10 cards be organized? Answer: 3,628,800 How: Product notation, they're 10 cards by using the factorial method, it will tell you how many combiniations. Equation/Work: 10 ∏ k =1*2*3*4*5*6*7*8*9*10=3,628,800 k=1