***Magic of Multiplying by 5*** 1). When multiplying by 5, it is easier to divide by 2 and multiply by 10. 2). If the number you are multiplying is odd, then the last number will be a 5, otherwise the last number is 0. Ex: 5 x 142 =_________. a) 142 ÷ 2 = 71. Write 71. b) Since 142 is even the last number is 0. Write 0. c) The answer is 710. Ex: 5 x 142857 =_______. a) 142857 ÷ 2 = 71428 with a remainder of 1. Write 71428. b) Since there is a remainder of 1, the last number is 5. Write 5. c) The answer is 714285. Note: This trick works because 5 = 10 ÷ 2.
Posted on: Tue, 07 Oct 2014 00:22:38 +0000
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