without using a calculator

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Stagga

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Jan 7, 2012
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Hey this question is easy but its extremely hard for me to figure out this kind of problem. Im studying the math part of the asvab and I can't use a calculator, so my question is how do 21/24 and 9/0.45? I know its 0.875 and the other is 20 but I need to know how to do it on paper. What's the process?
 
What I mean by "how do"is what's the step by step process by doing it on paper.
 
Stagga said:
21/24
9/0.45
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It may not be nearly as hard as you are thinking.

First, and foremost, give it a good estimate. This could be quite sufficient and no other effort would be required.

21/24 -- Since 21 isn't very far from 24, let's try somehting close to, but not exceeding one (1)! If the other answers are greater than one (1), discard them.

9 / 0.45 -- Again, nor far from 9 / (1/2) or 18. Pick something around 18. If the other answers are around 45 or 6, discard them.

Second, you must come to terms with what your score will mean to you. If you plan to be infantry or auto mechanic, why do you care if you do well on the math section? If you are planning on intel, or some other highly technical field, you had better step up your game.
 
tkhunny said:
It may not be nearly as hard as you are thinking.

First, and foremost, give it a good estimate. This could be quite sufficient and no other effort would be required.

21/24 -- Since 21 isn't very far from 24, let's try somehting close to, but not exceeding one (1)! If the other answers are greater than one (1), discard them.

9 / 0.45 -- Again, nor far from 9 / (1/2) or 18. Pick something around 18. If the other answers are around 45 or 6, discard them.

Second, you must come to terms with what your score will mean to you. If you plan to be infantry or auto mechanic, why do you care if you do well on the math section? If you are planning on intel, or some other highly technical field, you had better step up your game.
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Trust me that's what Im doing... my scores mean a lot to me and I want to do my best. Hence the reason why I join this forum. Second I divided 21/24 on paper I got a remainder of 3.... so how does that convert to the answer 0.875?
 
JeffM said:
It is hard to answer you because it is hard to know exactly what your question is. Please answer the following:

What is asvab?

What grade are you in?

Do you know how to do long division?

Do you know how to turn fractions into decimal notation?
I
Do you know how to divide by numbers in decimal notation?
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I'm in the 12 grade and I do know how to long division and algebra but like many I'm calculator depended. The asvab is a military test that determines what career is for me. I can't use a calculator so Im doing everything on paper. Those questions are examples of what I'm having trouble with.

Basically the question is how do I work out division problems that gives me answers like... 0.875 or 0.000547(those are just made up numbers) I can do long division that gives me simples answers like 34 or 109 and so forth. I want know the process in getting a decimal number like 21/24 which by using a calculator gives me 0.875..
 
Stagga said:
Yea I told you I'm mathematically slow lol no I don't understand can you please example it to me
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On second thought just by looking at it you simplified it... I know 7 can go into 21 and8 can to into 24.... but that's not what I'm looking for
 
Stagga said:
On second thought just by looking at it you simplified it... I know 7 can go into 21 and8 can to into 24.... but that's not what I'm looking for
Click to expand...

This is what I am talking about. A rough idea may be as valuable as an exact result. Just thinking about what is close, rather than worrying about exactly what it is, may be sufficient for your purposes. It is a multiple choice test in the math section. If all the answers are misleading, it's probably an unfair exam and it would not be allowed. Let's assume it is fair and valid. This MUST mean that some of the answers will be easy to rule out.

Change to Decimal: 21/24

A) 3.000
B) 2.000
C) 1.000
D) 0.875
E) 0.500

Three are immediately discarded. A fourth after only a little thought. Done.
 
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tkhunny said:
This is what I am talking about. A rough idea may be as valuable as an exact result. Just thinking about what is close, rather than worrying about exactly what it is, may be sufficient for your purposes. It is a multiple choice test in the math section. If all the answers are misleading, it's probably an unfair exam and it would not be allowed. Let's assume it is fair and valid. This MUST mean that some of the answers will be easy to rule out.

Change to Decimal: 21/24

A) 3.000
B) 2.000
C) 1.000
D) 0.875
E) 0.500

Three are immedaitely discarded. A fourth after only a little thought. Done.
Click to expand...

Ok can you show me the steps of how you change 21/24 into a decimal? Can you demonstrate that please?
 
Stagga said:
The asvab is a military test that determines what career is for me.
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This is not quite correct. More accurately, it determines which jobs are NOT available to you. It is easy to find a recruiter walking into a room full of recruits and saying something like this:

"An unusual MOS just opened up. It will be awesome."
{12 fresh recruits stand up and look interested}
"You need a minimum 72 on your ASVAB."
{10 fresh recruits sit back down}

Doug Adams says it can be "fun"!

http://www.military.com/ASVAB/0,,ASVAB_Tips_Math.html

Seriously, Stagga, if you're a High School Senior and you cannot reduce a fraction like 21/24, you are in real trouble if your life depends on your ASVAB score (or any other placement-like exam). You may wish to take another year and apply yourself in the actual study of elementary mathematics. Will a 1 year wait make that much difference in your life?
 
Stagga said:
Ok can you show me the steps of how you change 21/24 into a decimal? Can you demonstrate that please?
Click to expand...

You're not understanding me at all. I'm trying to convince you that the best way to turn 21/24 into a decimal is DON'T DO IT!

You are making a common error. You ask for help but insist that only one kind of help will do. This is not a beneficial attitude. You will have to trust someone else's opinion on how best to proceed. Open up your mind. Has this attitude been your past reason for failing to progress in mathematics? It can't help.

Shall we learn some mathematics, or will you insist on controlling your environment and making the same kind of progress you have made so far? I'm not trying to discourage you. I'm trying to get you to open up your brain and rethink your learning process that quite clearly has not served you all that well in the past. It's time to change styles - if you really want to learn.

My views. I welcome others'.
 
tkhunny said:
This is what I am talking about. A rough idea may be as valuable as an exact result. Just thinking about what is close, rather than worrying about exactly what it is, may be sufficient for your purposes. It is a multiple choice test in the math section. If all the answers are misleading, it's probably an unfair exam and it would not be allowed. Let's assume it is fair and valid. This MUST mean that some of the answers will be easy to rule out.

Change to Decimal: 21/24

A) 3.000
B) 2.000
C) 1.000
D) 0.875
E) 0.500

Three are immediately discarded. A fourth after only a little thought. Done.
Click to expand...

However, trouble will come if one of the options is "None of the above"
 
tkhunny said:
You're not understanding me at all. I'm trying to convince you that the best way to turn 21/24 into a decimal is DON'T DO IT!

You are making a common error. You ask for help but insist that only one kind of help will do. This is not a beneficial attitude. You will have to trust someone else's opinion on how best to proceed. Open up your mind. Has this attitude been your past reason for failing to progress in mathematics? It can't help.

Shall we learn some mathematics, or will you insist on controlling your environment and making the same kind of progress you have made so far? I'm not trying to discourage you. I'm trying to get you to open up your brain and rethink your learning process that quite clearly has not served you all that well in the past. It's time to change styles - if you really want to learn.

My views. I welcome others'.
Click to expand...

I see what your saying and thank you. All I'm trying to do is to understand this so I can practice without using a calculator. I really need the help
 
JeffM said:
First, tkhunny has given you AT LEAST two excellent pieces of advice

One is that you can learn because everyone can learn, but you need to be open to listening to learn. Never say you can't learn. It may be hard, but it is a LOT harder if you do not listen.

Second is that estimating is as good as being exact for many purposes, ONE of which may be scoring well on a multiple choice test.

OK Some quick review.

1: \(\displaystyle a\ /\ b\ is\ the\ same\ as\ \dfrac{a}{b},\ and\ means\ b\ is\ divided\ into\ a\)

So 21 / 24 must be less than 1 so you can reject a whole bunch of answers right away.

2. Simplifyfing fractions

\(\displaystyle \dfrac{a}{a} = 1\ for\ all\ a \neq 0\)

This fact let's you simplify many fractions

\(\displaystyle \dfrac{21}{24} = \dfrac{3*7}{3*8} = \dfrac{3}{3}*\dfrac{7}{8}= 1*\dfrac{7}{8} = \dfrac{7}{8}\)

Simple fractions are easier to work with

3. Converting fractions to decimals

Look at

http://www.youtube.com/watch?v=Gn2pdkvdbGQ
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THANK YOU! I hope I didnt offend anybody... I hope I didn't come across narrow minded... I guess I wasn't understanding. I am eager to learn and accept everybody's opinion. Thank you all
 
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