Teacher2Teacher 
Q&A #2599 
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From: Joe <josephsweeney@rcn.com> To: Teacher2Teacher Public Discussion Date: 2004071819:54:49 Subject: Re: Re: Re: Classroom Openers I am reminded of an old trick that might amuse you and egage the students. Have them pick a two digit number... Now begin to play with them; having them add, multiply, etc. to the number. In the end you can have them reach a specific number or the one they chose originally. You can work out your routine ahead of time by using algebra. Let the first digit of any number be A and the second digit (or one's column) be B. Then any student choice will equal 10A+B. Now play with the algebra. Divide their number by 2... (10A+B)/2 multiply it by 8 40A+4B subtract 20 and then divide by 2 : (40A+4B20)/2 = 20A+2B10 Add 10 multiply by three divide by six etc. Playing with three digits might mean letting them use their calculator and just use 100A+10B+C in your calculations.
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