Introducing Place Value to ChildrenDate: 10/01/2007 at 19:06:45 From: Auria Subject: teaching my son place value notations I'm wondering how to teach my son about place value. How can I show him that units are up to 9 then when it comes to 10 is tens and so on? I really get confused myself how to explain it to him. 1,2,3,4,5,6,7,8,9 are ones 10,11,12,13,14,15,16, up to 99 is tens and so on Date: 10/01/2007 at 22:58:20 From: Doctor Peterson Subject: Re: teaching my son place value notations Hi, Auria. I introduced place value to my children with several different models. One was beans, cups, and trays: I would put 10 beans in each cup, and 10 cups on a tray, while counting beans. Thus up to 9 would just go on the table, individually; when there were 10 they would fill a cup, and then I'd keep putting more on the table until there were another 10. Eventually I might have 1 tray of 10 cups (100 beans), and 3 additional cups (30), and 7 single beans, for a total of 137. The hundreds place represents the number of trays (1), the tens place the number of cups (3), and the ones place the number of single beans (7). This makes it clear that any numeral represents a number we can count, and any number of beans can be expressed this way. You can also do addition and subtraction with this system, and see how the digits work. Another model was play money, which is a little more abstract so it should be used after the beans are fully understood. A $10 bill represents a stack of 10 $1's; a $100 bill can be exchanged for a stack of 10 $10's, or 100 $1's. By always having no more than 9 of any one kind of bill, we represent a number's places, and can do addition and subtraction as with the beans. Our number 137 would be one 100, three 10's, and seven 1's. To add $84 to that, I would add 4 more $1's, but since I have 11 now and that's too many, I change 10 of them for a $10 and keep only 1 $1 in the pile. Now I have 3, plus 8, plus the new 1 $10's, for a total of 12 $10's; again I change 10 of those for a $100, leaving me with a total of 2 $100's, 2 $10's, and 1 $1. Another thing that was of interest was a mechanical counter, either one that works like an old odometer (if you can find anything like that any more), or the plastic counters they used to have where you could click any digit to add one. I don't know if anything like this can still be found easily! If you have any further questions, feel free to write back. - Doctor Peterson, The Math Forum http://mathforum.org/dr.math/ Date: 10/02/2007 at 22:32:30 From: Auria Subject: Thank you (teaching my son place value notations) Thank you so much for responding to my question. It will help me explain to my son in a much better and easier way. Auria. |
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