Math Is Fun Forum
  Discussion about math, puzzles, games and fun.   Useful symbols: ÷ × ½ √ ∞ ≠ ≤ ≥ ≈ ⇒ ± ∈ Δ θ ∴ ∑ ∫ • π ƒ -¹ ² ³ °

Login

Username

Password

Not registered yet?

#551 2013-03-14 04:03:37

mandy jane
Power Member

Offline

Re: Mandy Jane's Corner

have to go as husben is in will  do this for sunday ok? is that is allright with you i will be on here sunday at 2.00pm/ send message back please and some more sums as well?

#552 2013-03-14 04:20:59

SteveB
Power Member

Offline

Re: Mandy Jane's Corner

Yes that's fine.
See you on Sunday.
I know this is a difficult one, but how about 12.1 - 0.589 ?
(I need to know whether you can do the 1.3 - 0.716 question though, if you can't do that one then you
won't be able to do the one above.)
Of course you can ask questions and add posts in between now and Sunday and we could exchange a few
posts at disjointed times. You have done these questions better and more quickly than I had thought you would.
I could do with knowing whether you want to do multiplication and division and what sort of question.
You are almost there with subtraction already and at the rate you did those other questions it shoudn't take very
long. I found it difficult to keep up and I was the one setting the questions.
Just to test you as to what you know already how about:
3.46 x 7 ?
3.46 x 0.7 ?
1.89 divided by 7 ?

#553 2013-03-14 21:25:56

mandy jane
Power Member

Offline

Re: Mandy Jane's Corner

Hi steveb mandy here. As you will know if you talk to to bob bundy he will tell you that i have trouble with time table and deviding like long deviding? Hope you can read this as i am dyslexit and find it hard? Leave message on here or send e-mail and i will get back to you ok?

#554 2013-03-14 23:15:18

SteveB
Power Member

Offline

Re: Mandy Jane's Corner

I think we need to finish off the subtraction bit. I will do 1.3 - 0.716 as an example:
It is helpful to add two extra zeros on the end of 1.3 - this does not effect what the number actually
is and enables us to line up the two numbers correctly:
1 . 3 0 0  -
0 . 7 1 6
----------

----------
Now 0 - 6 won't work because it is a negative result. Looking to the left the next number is a
zero so that is no good. Looking to the left again we have a "3", we can reduce this to 2 and
drop a 9 to the right instead of the first zero and increase the second zero to ten.
So we end up with something like this (of course there will be a few crossings out in a hand written
test or assignment - the 3 and the first 0 are crossed out in this case).
1 . 2 9 [10]  -
0 . 7 1   6
-------------
        8   4
-------------
Note that I have filled in the two numbers 4 and 8 which are now easy to work out.
Now 2 - 7 is going to be negative as well so let's borrow from the 1 to the left.
The 1 at the top left gets crossed out and replaced by a 0.
Then we have to add 10 to the 2 because this is worth ten times as much in this column:
0 . [12] 9  10
0 .  7    1    6
-----------------
0 .  5    8    4
-----------------
As you can see I have finished off the answer. 12 - 7 is now easy. The left most column is
very easy 0 - 0 = 0 .
Notice that I have added the decimal point being careful to get it in the right place.
If you so wish you could do 12.1 - 0.589 as a similar problem to check that you have
understood what I have explained.
It would be interesting if you post it to this site or via email so I can see if you are correct
and doing it correctly and I will help if you need some help.
I think we had better delay the multplication and division for a bit. I was jumping ahead a
bit because I thought that you were coping very well with the addition.
You can of course make up your own examples and try them to see if you can do them
check them with a calculator and obviously if you have managed to find something that
you are stuck on by all means post it here or email it to me. Practice is a good way to
learn some basic maths. You cannot learn maths as you might read a novel.
I do entirely understand about your dyslexia. If you cannot do times tables from 2 to 9
then you will not be able to do multiplication and division very well. We need to discuss
this a little and it might be better if we discuss that and a few other things about what
other topics to deal with etc. we can discuss this via email if you prefer.

#555 2013-03-15 07:24:14

anonimnystefy
Real Member

Offline

Re: Mandy Jane's Corner

Hi SteveB

Welcome to the forum! smile


The limit operator is just an excuse for doing something you know you can't.
“It's the subject that nobody knows anything about that we can all talk about!” ― Richard Feynman
“Taking a new step, uttering a new word, is what people fear most.” ― Fyodor Dostoyevsky, Crime and Punishment

#556 2013-03-16 20:01:36

SteveB
Power Member

Offline

Re: Mandy Jane's Corner

Hi anonimnystefy. Thanks for your welcome post.

#557 2013-03-16 20:10:08

mandy jane
Power Member

Offline

Re: Mandy Jane's Corner

Hi steveb. Mandy here. I will send you an email later today about my maths ok? I just wanted to say that it is good to finally get a tutor for my maths?

#558 2013-03-16 21:42:25

SteveB
Power Member

Offline

Re: Mandy Jane's Corner

Yes that's fine.
It looks like I am going to be in for more of today than I previously expected.

#559 2013-03-17 01:45:54

mandy jane
Power Member

Offline

Re: Mandy Jane's Corner

hi steveb mandy here i have sent you an e-mail ok? can you read it please?

#560 2013-03-17 02:22:27

mathgogocart
Super Member

Offline

Re: Mandy Jane's Corner

mandy jane wrote:

hi mandy here can anyone else give me any advis on what to from message 465 that bob bundy sent me on maths then? if so leave me a message on here please?

i would go with MIF cause free


Hey.

#561 2013-03-17 02:24:53

mandy jane
Power Member

Offline

Re: Mandy Jane's Corner

hi mathgogocart mandy here. how do you think i am doing with my maths then? send message back please?

#562 2013-03-17 02:35:04

mathgogocart
Super Member

Offline

Re: Mandy Jane's Corner

mandy jane wrote:

hi mathgogocart mandy here. how do you think i am doing with my maths then? send message back please?

Good.What do you want me to teach?


Hey.

#563 2013-03-17 02:38:18

mandy jane
Power Member

Offline

Re: Mandy Jane's Corner

how do you do decimal subtraction then? can you show me please?

#564 2013-03-17 04:10:38

SteveB
Power Member

Offline

Re: Mandy Jane's Corner

Right. How about I do that instead. Now 1.3 - 0.716 ?

It can be set out like this:
1.300 -
0.716
------

------
0 - 6 will give us a negative number. So what do we do ?

#565 2013-03-17 05:02:08

SteveB
Power Member

Offline

Re: Mandy Jane's Corner

I am going to see with this post whether I am allowed to post a graphics file.
Hopefully this will illustrate 1.300 - 0.716
Note that I have included the headings "units, tenths, hundredths, thousandths".
Obviously in an exam you would not waste time writing these things unless they were asked for.
However, Mandy, it may be a good idea to put these things in a few times to get the
hang of place value concepts.
OK let's see whether the graphic works...


Uploaded Images
View Image: SubtractPic.gif      

#566 2013-03-17 06:23:25

SteveB
Power Member

Offline

Re: Mandy Jane's Corner

Whoops! Sorry about that I have got two subtractions muddled in my head.
I meant to ask about the one that went 12.1 - 0.589
I have already done a worked example for 1.3 - 0.716
However if you did not read the worked example (Mandy) then you could still have a go.

#567 2013-03-18 01:50:45

mandy jane
Power Member

Offline

Re: Mandy Jane's Corner

Hi steveb mandy here. Sorry about yesterday but when you come on my husband had just got in from working at the ipswich football club?  We have been out this morning and just got back? I need to do the maths you gave me so I will be back on here at around 7.00 pm if this is okay with you? Can you leave me a message on here please?

#568 2013-03-18 01:51:27

SteveB
Power Member

Offline

Re: Mandy Jane's Corner

Hello (Mandy) I have noticed that you are logged on....

#569 2013-03-18 01:58:29

SteveB
Power Member

Offline

Re: Mandy Jane's Corner

Ah. I see. By the way one of the subtraction questions I was going to ask you was to try 113.7 - 66.328 ?
I know that may look hard, but it is not as difficult as all that if you know about decomposition/borrowing.
I have thought of some material on multiplication and division, but if I post it now it might get a bit buried.
I will leave it for now, but if you want me to post my long division now for you to preview let me know.
The multiplication will take longer because I have still got to work out whether I am going to use a graphic and
have not typed anything, but I have made some notes on paper.

#570 2013-03-18 02:37:23

mandy jane
Power Member

Offline

Re: Mandy Jane's Corner

Hi steveb mandy here. 1 1 3.  7 0 0
                                  0 6 6.  3 2 8
                                  ---------------
                                   0 4 7. 3 7 2
                                   --------------
Is this correct then?  Can you post long division now for me to preview please?

#571 2013-03-18 03:45:08

bob bundy
Moderator

Offline

Re: Mandy Jane's Corner






You cannot teach a man anything;  you can only help him find it within himself..........Galileo Galilei

#572 2013-03-18 03:49:46

mandy jane
Power Member

Offline

Re: Mandy Jane's Corner

Hi bob bundy mandy here. -do you think my maths is going then?

#573 2013-03-18 04:11:13

SteveB
Power Member

Offline

Re: Mandy Jane's Corner

Doing 171 divided by 3 using long division:


    0 5 7
   -------
3 | 1 7 1
    0
    -
    1 7
    1 5
    ---
      2 1
      2 1
      ---
      0 0
      ---

Times table reminder: [0, 3, 6, 9, 12, 15, 18, 21, 24, 27]

First step: observe that 1 divided by 3 is 0 remainder 1.
So put the 0 above in the answer, Do 1 minus 0 = 1.
Then drop down the 7 to make it into 17.

Aside: 3 x 5 = 15  so put the 5 up in the answer and subtract the 15.

The result of that is 2, then drop down the 1.
This makes 21.

Aside: 3 x 7 = 21  so put the 7 up in the answer and subtract the 21.

Now we end up with zero and there are no more numbers to drop down
the division is completed.

Often arrows are used to show the numbers (7 and 1 in this case) that
are dropped down. It is rather messy to show this using plain text, but
I have made up a graphical file to help show this.

------------------------------------------------------------------------

The short division version is difficult to display with plain text, but
it looks like this:

   ---------
3 | 1  7  1

then:  the "1" remainder goes in front of the 7 to make it look like 17.
    0 
   ---------
3 | 1 [17] 1

the "2" remainder goes in front of the 1 to make it look like 21.
    0  5    7
   ------------
3 | 1 [17] [21]

Notice that all of the calculations are the same, but that some of the information
displayed in long division does not get written down unless you want to add a few
notes down below the division or to the side. It is more compact and okay for simple
case where the thing that we are dividing by is small, but usually if we are dividing
by a number out of range of your times tables then long division is better.


Uploaded Images
View Image: LongDiv171div3.gif      

#574 2013-03-18 04:24:29

SteveB
Power Member

Offline

Re: Mandy Jane's Corner

Now a slightly harder one on long division, but still fairly easy:

     0 6 3
    ------
7 | 4 4 1
     0
     -
     4 4
     4 2
     ---
       2 1
       2 1
       ---
       0 0
       ---

Each time we choose the highest number below or equal to the remainder
added to the number dropped down, in the times table of the number we
are dividing by.

[ 0, 7, 14, 21, 35, 42, 49, 56, 63 ]

So for example if the number we are left with is 44 after a 4 is put on
the end of remainder 4 then as you can see 42 is the number in the 7 times
table to put under 44.

If we put anything smaller down say 35 then it would go wrong because we
would end up with the remainder being too high - eg. 44 - 35 = 9
this is too high because with a division by 7 each remainder needs to be
in the range (0, 1, 2, 3, 4, 5, 6).
If we choose the multiple of 7 to be 49 with 44 as the number left, then that
would be too high because the subtraction is 44 - 49 = -5 which is too low
to be in the range (0, 1, 2, 3, 4, 5, 6).

I must admit that long division when I was taught it at school was intended
for dividing by a number of at least 13 so perhaps I should do a more
advanced example next.


Uploaded Images
View Image: LongDiv441div7.gif      

#575 2013-03-18 04:57:41

SteveB
Power Member

Offline

Re: Mandy Jane's Corner

OK. A question for you to attempt:

16549 divided by 13. (Using long division)

[0, 13, 26, 39, 52, 65, 78, 91, 104, 117]

I have prepared an image with the answer.

Board footer

Powered by FluxBB