thowell Posted October 19, 2015 Share Posted October 19, 2015 We are doing Fundamentals of Math this year and Dd12 has been doing fine. However, we started chapter 2 today and she needed to write decimal numbers in expanded form using exponents. She totally hit a wall!! Thing is I am unsure how to explain this to her. I know how to do it and what it means but I cant figure out how to make her understand it. She seems to be having trouble understanding the decimal place value period. I dont know how she passed the intro section on decimals but she definitely does not understand what the numbers to the right of the decimal mean!! I was never taught math from a conceptual point so I may not really understand it either. So how to explain this to her??? I was thinking of getting the LOF Decimal books as the Fraction book is what finally made fractions click for her. Any other suggestions?? Quote Link to comment Share on other sites More sharing options...
mom31257 Posted October 20, 2015 Share Posted October 20, 2015 The LOF Decimal book would be a good choice, especially since the Fractions book helped. I have the book and don't see any answers in the back using expanded form, but maybe it would help her understand decimals better. Maybe it's that she doesn't understand the exponents more than decimals. Did the curriculum have you write the decimal in expanded form using fractions before doing the exponents? For example: 0.2456 would be 2 x 1/10 + 4 x 1/100 + 5 x 1/1000 + 6 x 1/10,000 If so, how did she do with that? Does she understand that 10 is 10 to the 1st, 100 is 10 to the 2nd, 1000 is 10 to the 3rd and so on? If she does, then she could write the above expansion first, then write it again with the exponential form in the denominator of the fraction. (2 x 1/10 to the 1st) The next step would be understanding negative exponents and that 1/10 to the 1st can be written as 10 to the negative 1, 1/10 to the 2nd can be written as 10 to the negative 2, and so on. She could replace all those fractions with their respective negative form, (2 x 10 to the negative 1). Here is a video you might could use. It doesn't do the very last step of replacing the fractions with the exponent, though. http://pdevoto.reedschools.org/decimals/decimals-in-expanded-form-with-exponents Here is a calculator which will do expansions for you. It might help to see several examples. http://www.calculatorsoup.com/calculators/math/expanded-form-calculator.php 1 Quote Link to comment Share on other sites More sharing options...
Tiramisu Posted October 20, 2015 Share Posted October 20, 2015 I think the Decimal books in the Key to Series may help. Quote Link to comment Share on other sites More sharing options...
MrSmith Posted October 20, 2015 Share Posted October 20, 2015 Is it the decimals or the negative exponents? One can understand that 0.1 = 1/10 without understanding it is also 10 raised to minus 1. Quote Link to comment Share on other sites More sharing options...
thowell Posted October 21, 2015 Author Share Posted October 21, 2015 Is it the decimals or the negative exponents? One can understand that 0.1 = 1/10 without understanding it is also 10 raised to minus 1. I actually think it is both. We have backed up with the Decimals 1 book from MM and will work through the decimal books and LOF. This is the first year we have used BJU and they did introduce exponents in the previous lesson but this seemed like a big jump to me. 1 Quote Link to comment Share on other sites More sharing options...
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