Teacher2Teacher |
Q&A #6001 |
From: Marielouise
(for Teacher2Teacher Service)
Date: Mar 22, 2001 at 16:08:06
Subject: Re: Reciprocals
Hi, Julie, This is your lucky day. What i found is not exactly what you wished but you could make it. I was planning for a family math session today and opened the Family Math book to: "The Lost Number." (249). This activity is to practice pattern recognition and to reinforce the understanding of inverse relationships or reciprocals for multiplication. In order to do this activity you will need to have a calculator for each pair of children that has the "constant divide feature." The text advises parents to practice before doing this with their child. I suggest that you do so also before using it with your class. You can set up the "constant divide" feature by pressing the divide key, then a number, then the equal sign. For example: / 782 = will set the calculator to divide by 782 any number that is entered into the calculator GAME: 1. hide a number in each of the pair's calculator. 2. tell this story: One day Aunt Bebe called all of the neighbor children together and told them that she had just discovered that there was a number lost in her calculator. She needed their help in finding out what the number might be. She said the instructions that had come with the calculator said: if a number gets lost, then • enter a three digit number • enter = • write down the answer as this is a clue! • continue to enter three digit numbers and = to collect clues. • the three digit number that gives the answer of 1 is the LOST NUMBER. It took Aunt Bebe ten guesses to find her number. How many guesses do you think it will take you to find the number lost in this calculator. The Family Math book gave an example for the number 782. The guesses were 123 = too small 100 = too small 999 = too big 888 = too big 777 = too small but closer than 123 and 100 788 = too big but closer than 888 780 = too small 785 = too big 782 = 1 the Lost Number. This could be a chance to discuss what the clues told you. The exercise could also help you talk about the reciprocal being equal to the number. You mentioned that you had to help them change the number to a mixed number or decimal. This game would encourage them to use decimals if you use decimals in putting in the number -Marielouise, for the T2T service
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