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HELP!!

I'm looking at Lesson 68 #28 (3rd edition)

Use two unit multipliers to convert 144 square feet to square miles. Round any decimal answer to two places.

I have the solution manual and my son and I got to this partial answer

144 divided by (5280)(5280) miles squared

It looks from both the answer key and from the directions in the problem (to round any decimal answer to two places) that we are actually supposed to divide this problem out. And as far as I know we are not using calculators at this point. So are we to do this with pencil and paper? I tried to work it on the calculator but it has so many places that the calculator did not give the answer the book has.

We simplified the problem down to 1 divided by 193,600. But even then I could not divide this out with my pencil and paper. Are my long division skills rusty? I have not encountered any problem like this in Saxon up to now.

The key gives the answer as 5.17 x 10 to the negative 6 power

Is there a trick to getting that answer without sitting down to the biggest long division problem I think I've ever tried to tackle? I'm kind of frustrated with it. Any insights would be so much appreciated. I want to throw the math book through the window at this point. :tongue_smilie:

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I don't use Saxon, but I've got the same answer they have.

You're correct to use 144/5280^2, and it does reduce to 1/193600.

Not having the same answer could depend on the model calculator you use. You need to be using one that has scientific notation. I'm interested in hearing if anyone did this longhand. Sounds like one designed for the calculator (and a great illustration of why the metric system would be much easier - just move the decimal!).

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It's not that the calculator was wrong exactly. I probably didn't word that right. But there were not enough places to get the 5.17. It was something like .00000051 (I don't know exactly how many zeros it listed) But aside from a lesson or two specifically on the calculator I didn't think it was time to break it out and it hasn't been mentioned in the text to do so, as far as I know.

Is there some trick to dividing numbers manually (w/o a calculator) with a 6-digit divisor. I'm sure I've never done such a thing and don't think there was ever a previous Saxon lesson on it. But I don't read every lesson anymore. Only the ones that ds has trouble with. This particular problem was taught in lesson 33, if I remember correctly. I did read this one to refresh my memory on changing units. There was nothing about dividing such large numbers. I'm quite baffled why this would be in there.

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Sounds like it's time to get a scientific calculator. In the Saxon algebra books, they tend to give the answer as 144/(5280)(5280) and leave it at that. No need to do the calculations by hand. :tongue_smilie:

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