needing help with simplifying -25 divided by 6 plus 4 1/5

TaraKay

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Jan 11, 2007
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I am trying to teach my son math and can not get this problem to come out with the answer that the book has. If someone could tell me step by step what to do I would really appreciate it. Thank you. -25 divided by 6 + 4 1/5 =
 
This? \(\displaystyle \L\;\frac{-25}{6\;+\;4\frac{1}{5}}\)? That's really ugly. We really cannot tell you what you are doing wrong if you don't tell us what you are doing.

Get rid of the silly mixed fractions. The are good for almost nothing except visual comparisons.

\(\displaystyle \L\;4\frac{1}{5}\;=\; \frac{20}{5}+\frac{1}{5}\;=\;\frac{21}{5}\)

That leaves us with this.

\(\displaystyle \L\;\frac{-25}{6\;+\;\frac{21}{5}}\)

Add things in the denominator

\(\displaystyle \L\;6\;+\;\frac{21}{5}\;=\;\frac{30}{5}+\frac{21}{5}\;=\;\frac{51}{5}\)

Now we're down to:

\(\displaystyle \L\;\frac{-25}{(\frac{51}{5})}\)

That's the same as:

\(\displaystyle \L\;(-25) *\frac{5}{51}\)

Okay. You either take it from there or tell me I'm working the wrong problem because you actually meant \(\displaystyle \L\;\frac{-25}{6}\;+\;4\frac{1}{5}\).
 
The page we are working on is called Order of operations with rational numbers. I do not know how to get the computer to show the dividing sign and that is why I wrote it out. But the problem is- Negitive 25 divided by 6 plus 4 and 1/5. The book says that the answer is 1/30 and no matter how I do it I can't come up with that answer. Sorry I didn't make myself clear, hope it is better now.
 
tkh will be happy to know it was his 2nd thought regarding the expression ...

\(\displaystyle \L -25 \div 6 + 4\frac{1}{5}\)

do the division first ... \(\displaystyle \L -25 \div 6 = -4\frac{1}{6}\)

\(\displaystyle \L -4\frac{1}{6} + 4\frac{1}{5} = \frac{1}{5} - \frac{1}{6} = \frac{6}{30} - \frac{5}{30} = \frac{1}{30}\)
 
TaraKay said:
The page we are working on is called Order of operations with rational numbers. I do not know how to get the computer to show the dividing sign and that is why I wrote it out. But the problem is- Negitive 25 divided by 6 plus 4 and 1/5. The book says that the answer is 1/30 and no matter how I do it I can't come up with that answer. Sorry I didn't make myself clear, hope it is better now.

You can use / as dividing sign:
-25/6 + 4 + 1/5
 
Thank you very much. I just could not get it to come out right and now I know what I did wrong. About using / as a dividing sign how would you know if i meant it as a fraction? I could not find the dividing sign on my keyboard, how did you guys get it?
 
TaraKay said:
Thank you very much. I just could not get it to come out right and now I know what I did wrong. About using / as a dividing sign how would you know if i meant it as a fraction? I could not find the dividing sign on my keyboard, how did you guys get it?
Tara, a fraction is a division.
Like, 4 and 1/5 means 4 plus 1 divided by 5.

Take fraction 6/2: that's 6 divided by 2 = 3, right?
 
Thanks but I meant how did the dividing sign and the fractions show up the right way in the answer. What are you pushing on the keyboard to get it to show up? [/code]
 
TaraKay said:
Thanks but I meant how did the dividing sign and the fractions show up the right way in the answer. What are you pushing on the keyboard to get it to show up?
They were using LaTeX. Information on using LaTeX for formatting is available by following the links in the "Forum Help" pull-down menu at the very top of this page.

Eliz.
 
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