Mandy Jane's Corner

SteveB · 2013-07-26 00:01:02

About the email I have just sent:
Just out of interest: I sent that at 12:57 - when did you get the email?

Last edited by SteveB (2013-07-26 00:03:08)

mandy jane · 2013-07-26 00:04:02

Hi steveb I got. It at 12.58 ok I will bring here at7.00 tonight ok send messages back now please?

SteveB · 2013-07-26 00:06:03

1 ounce = 28.3495 grams (perhaps round to 28g)
(use exact figure if more accuracy is needed then round at the end)
So for instance how many grams in 6 ounces ?

6x28.3495 = 170.097

How many ounces is 100 grams ?

100 / 28.3495 = 3.527....

To the nearest whole number there are 170 grams in 6 ounces.
To 1 d.p. accuracy there are 3.5 ounces in 100g.

Last edited by SteveB (2013-07-26 06:14:16)

SteveB · 2013-07-26 06:26:51

(3) Convert 15cm into inches.
(4) Convert 1 foot into metres

Obviously the question (3) can be worked out more or less with a 15cm ruler.
An exact answer would be 15 / 2.54 = 5.91 inches to 2 d.p.

For question (4) we need to convert the foot into inches so 12.
Then take 12 and convert into cm. 12 x 2.54 = 30.48 cm

Then this needs to be in metres so 30.48 / 100 = 0.3048 m

I have decided to leave full accuracy in my question (4) answer.

Last edited by SteveB (2013-07-26 06:28:11)

SteveB · 2013-07-26 06:33:14

Worked example based upon the question about calculating someone's height from feet and inches into metric form.

A person is said to be 5 foot 9 inches tall exactly.

(1) How many inches is the person is just using inches ? (Hint: 12 inches equals one foot.)

5 x 12 = 60
Then 60 + 9 = 69
The person is 69 inches tall.

(2) Now convert this into centimetres. (Remember: 1 inch = 2.54 cm)

69 x 2.54 = 175.26 cm

(3) Now convert this into metres.

175.26 / 100 = 1.7526 m

(4) You could also put this in the form of metres and centimetres.

1 metre and 75 cm to the nearest cm.

SteveB · 2013-07-30 00:57:29

Mandy: Do you want to carry on with conversion or go back to one of the other everyday maths topics?

Last edited by SteveB (2013-07-30 00:59:36)

mandy jane · 2013-07-30 01:02:04

Hi steveb mandy here i had a look at the dyslexia forum Page it looks good. Should I do what we are doing send a message about maths and see what comes back regularly me?

mandy jane · 2013-07-30 01:05:35

Hi steveb I had a look at the dyslexia forum Page it looks good. Should I send a math question on there and see what comes back to me then?

SteveB · 2013-07-30 01:07:49

I don't remember whether that one has anything to do with maths. I think you should leave maths to this site.
That one seemed to me to be about dyslexia with a whole load of sub forums for dyslexic management issues.
For now I think you ought to bring up anything about maths that you want me to discuss.

I have just looked again at the website I suggested and I can't see any sub forum in there to do with maths.

However there is a massive load of information about dyslexia.

How well are you understanding the conversion topic?

Last edited by SteveB (2013-07-30 01:19:08)

mandy jane · 2013-07-30 01:18:41

Ok. Could I have work on capacity like litres/millilitres and centilitres?

SteveB · 2013-07-30 01:21:08

Updated explanation concerning: Cubic metres, litres, decilitres, centilitres and millilitres (or cubic centimetres).

A cubic metre is defined as being the volume of 100cm x 100cm x 100cm.

A litre can be regarded as the volume of a 10cm x 10cm x 10cm cube of something.

A decilitre is one tenth of a litre that is to say 10 times smaller than a litre and is 100 millilitres.

A centilitre is one hundredth of a litre that is to say 100 times smaller than a litre and is 10 millilitres.

A millilitre is one thousanth of a litre that is to say 1000 times smaller than a litre. One cubic centimetre = one millilitre

Although the millilitre is the same as a 1cm x 1cm x 1cm cube in volume notice that you cannot do this
with a centilitre or a decilitre without an irrational decimal to make the unit length of such a cube despite this the total
volume is a nice round number relative to the others.

Here is a summary of the terms on the left, then how many litres that is, then the perfect cube form of it with
a side length from the cube root of the number of cubic centimetres, and in square brakets the method for getting
the side length in cm of the perfect cube:

litre = 1 litre = 10cm x 10cm x 10cm [cube root of 1000]
decilitre = 0.1 litres = 4.64158883361cm x 4.64158883361cm x 4.64158883361cm (to 11 d.p.) [cube root of 100]
centilitre = 0.01 litres = 2.15443469003cm x 2.15443469003cm x 2.15443469003cm (to 11 d.p.) [cube root of 10]
millilitre = 0.001 litres = 1cm x 1cm x 1cm [cube root of 1]

(One million millilitres make up a cubic metre notice you have to do 100 x 100 x 100 to get a million or 1000 x 1000)
(one cubic metre = 100cm x 100cm x 100cm = 1,000,000 cubic centimetres or one million cubic centimetres or one million millilitres)

Mandy: It wouldn't hurt for you to read that bit above, but the maths of volume ratios in 3 dimensions goes
rather beyond the scope of the level you are studying, but if it helps you learn it then by all means learn
it in the above style and perhaps repeat the cube root calculations using a scientific or graphics calculator.

(Needless to say in practice even an engineer does not usually need to calculate something like that to 11 d.p.
if you can only measure to 3 signifcant figures then the answer is going to have about the same accuracy)

Last edited by SteveB (2013-08-03 04:07:57)

mandy jane · 2013-07-30 01:22:18

Here is a list of what else I have to do? Temperature / area,perimeter and volume / shape / extracting and illustrating date / averages and probability is this ok or not let me know please?

SteveB · 2013-07-30 01:30:24

With temperature we can do Fahrenheit and Celcius (or Centigrade - which does your course use out of interest?).

To convert into Centigrade from Fahrenheit you do the following:

start with degrees F subtract 32 then divide by 9 and multiply by 5

To convert the other way it is:

start with centigrade divide by 5 multiply by 9 then add 32.

So for example: 32F is the temperature at which water freezes. Subtract 32 then divide by 9 and multiply by 5.
Since we get zero the division and multiplication has no effect. We get 0C, or just zero Celcius/Centigrade.

Another example: 50F subtract 32 and we get 18. Then divide by 9. We get 2. Then mutiply by 5. We get 10.
Answer: 10C or 10 Celcius or 10 centigrade.

What is 68 Fahrenheit in Celcius ? (From now on I will call it Celcius to save me time typing both versions.)

Last edited by SteveB (2013-07-30 01:37:18)

mandy jane · 2013-07-30 01:34:29

The course use fahrenheit and Celsius ok? What else do you want to know please?

mandy jane · 2013-07-30 01:42:20

68 ÷ 9 x 5 = 37.7777777777778 am. I right?

SteveB · 2013-07-30 01:45:31

You have missed out an important bit of the calculation. You were supposed to subtract 32 first.

This sort of conversion involves an add/subtract bit of it which makes it a more complicated conversion than the others.

Try again?

SteveB · 2013-07-30 01:49:36

68 - 32 = 36

36 divide 9 = 4

4 x 5 = 20

The answer is 20 Celcius. (68 Fahrenheit)

Last edited by SteveB (2013-07-30 04:05:13)

SteveB · 2013-07-30 01:54:01

How about converting 86 Fahrenheit into Celcius ?
86 - 32 = 54
54 / 9 = 6
6 x 5 = 30
Answer: 30 C

Also what is 100 Celcius in Fahrenheit ?
100 / 5 = 20
20 x 9 = 180
180 + 32 = 212
Answer: 212 F

What is 104 Fahrenheit in Celcius ?
104 - 32 = 72
72 / 9 = 8
8 * 5 = 40
Answer: 40 C

What is 15 Celcius in Fahrenheit ?
15 / 5 = 3
3 * 9 = 27
27 + 32 = 59
Answer: 59 F

What is minus 10 Celcius in Fahrenheit ? (Notice that is below zero in Celcius, so expect an answer below 32 F)
-10/5 = -2
-2 * 9 = -18
-18 + 32 = 14
Answer: 14 F

Notice that when converting Celcius into Fahrenheit we can do: 1.8 C + 32 = F
When converting Fahrenheit into Celcius we can do: (F - 32) / 1.8 = C
Where C is the temperature in Celcius and F is the temperature in Fahrenheit. In other words using algebra for this conversion.
Notice also that (9/5) = 1.8

Last edited by SteveB (2013-08-01 05:06:08)

mandy jane · 2013-07-30 01:54:48

Ok will do that for you tomorrow ok? Is that ok

SteveB · 2013-07-30 01:56:03

Okay. I might leave a few more questions on here later. Bye for now.

A few on volume for you to puzzle over:

(1) What is 500 millilitres converted into centilitres?

500 / 10 = 50 centilitres

(2) What is 500 millilitres converted into litres?

500 / 1000 = 0.5 litres

(3) What is 200 litres in cubic metres?

200 / 1000 = 0.2 cubic metres

(4) What is one pint converted into litres? (Hint: there are 1.7598 pints in one litre. This is using UK conventions not US conventions.)

1 / 1.7598 = 0.5682.... litres
So there are 0.568 litres in a pint to 3 d.p. using the UK imperial pint definition.

(Apparently the US convention is that there are 473 millilitres in a US liquid pint. In UK there are more millilitres than that
in a UK imperial pint. It is the UK version that I was referring to in question 4)

Notice that for instance with question (4): no of litres x 1.7598 = no of pints
no of pints / 1.7598 = no of litres
I was taught to imagine 'dividing both sides of the equation by 1.7598' to get the second. More on that when you do algebra.
(I have improved #1236 a bit let me know if you don't agree with any of it. However I believe it is all correct)

Last edited by SteveB (2013-08-01 09:16:31)

SteveB · 2013-08-11 02:55:11

The math is fun dot com (teaching part of this website) does in fact have a tool in which it is possible to show
a graph for the conversions from Celcius to Fahrenheit, and Fahrenheit to Celcius.

Assuming I have not made any mistake, the two graphs should display in the image with this post.

mandy jane · 2013-08-16 02:56:40

Hi bob bundy mandy here i am finding the maths course hard to do? What do you think I should do? Do you think a college course would be good or not? Send me a message back on here or email me back please?

bobbym · 2013-08-16 03:04:10

Hi;

I am watching your progress. It is supposed to be hard. I have been struggling with it my entire life. That does not mean you should give up! You are learning things, continue.

mandy jane · 2013-08-16 03:10:38

Hi bobbym mandy here what do you think I should do stay with this maths course or go to. College? Send me message back now and let me know?

bobbym · 2013-08-16 03:17:20

If you want to go to college, then do that.

But, never leave anything where someone who knows more wants to teach you. That person is your best friend in the whole world. I would rivet myself to this place. And that is what I have done.

Math Is Fun Forum

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