no wonder adding up is tricky…

If you are asked to do an addition you are really being asked to

add the coefficients of a polynomial equation

Look , here’s what 326 really means:


3 is the coefficient of the second power, 2 is the coefficient of the first power and 6 is the coefficient of the zeroth power.


huatou: why polynomial?

good adder results

Here’s a list of the main ideas that are useful in becoming ‘a good adder’ generated from the previous post:

interpreting the meaning of numerals and operation symbols

to know the complements to and from 10 and to and from 5

immediate recognition of number pairs as complements 

the transference of the above to all other decades and patterns

familiarity with the inner structure of numbers

scanning problems first as a  fundamental activity

awareness of equivalent transformations after the scanning process

the power of  visual images of relationships and processes within memory

total awareness of the commutative rule 

total awareness of our number system including place value

transformation is OK and is allowed

generation of own recording styles


what makes a good adder?

When I was professor of wooden sticks at the university of Pokelsaltz I did a little experiment with some students. I gave them some little ‘sums’ and asked them to do them, taking note of how they did them and what actually they did and what thoughts occurred to them…

2 + 2 

recognised the symbol 2

recognised the + sign

was aware that an operation is actually possible

an awareness that these marks carry  meaning but that the marks are an immense abstraction from the external reality that was their origin

immediate knowledge of the answer – did nothing – just knew it was 4

didn’t scan it – didn’t read it – just knew

it trips a picture of equal groups

it looks like a symmetrical pattern to me – two halves of four

2 + 8

pairs that make ten – complements

didn’t do anything- just knew

recognised these as a way of making 10

it just looks like ten to me

I saw it and my eyes gravitated to the 8. I knew it was ten

you’d be crazy to count on eight

I think I’d do it backwards if I didn’t know it made 10

I have an image of 10 being a lot of other things – 10 is the destination – it isn’t one thing

10 has inner structures- I suppose all numbers do

you have to know the commutative rule

if you’re little it would be best if you had the confidence to scan it first rather than do it bit by bit from the 2. You’d save yourself a lot of trouble

12 + 3

I know that I can do the 2 plus 3 bit and basically that’s it  but I imagine that’s not obvious to little children

I see 5 and I see it in the teens

I have a picture of it living above 10 but before 20

I just know the answer

you could count on from 12

the 1 feels completely separate from the 2 – I know it s to do with place value – some people might not have that feeling

when I see “12” I see 10 and 2 – 12 doesn’t look like “one squiggle”, one thing. I see it as something to do with ten and some more

3 + 14

I know I have to add the 3 and the 4 and I know straight away that that’s 7

the 3 and the 4 belong to the same family – they live in the same room

I know you can ignore the 1,  because its different

you have to know the commutative rule or you’re in trouble

it’s best to scan the whole thing again first

it looks worse than the previous one – there the 2 and the 3 were together, now they’re separated by a 1 and the 1 is not really a 1, it’s a ten

place value is really important  but I bet it’s not easy to see it and understand it at first

we’re a long way away from a beginner aren’t  we? I suppose it’s like that with reading

In a way this is reading for meaning isn’t it?

15 + 6

I can see five’s in there

There’s two five’s and a spare 1

In my head I can hold the  first ten, see two five’s making another one, so that’s twenty, then add on the 1 to make 21

I see fifteen, a five and a one, so I know its 21

it’s a kind of making up to twenty

you have to know the five family

you have to know the way that five’s march on

when you look at the 15 it sort of sets your mind into knowing you’re looking for 5 more and so when you perceive the six, you see the 5 and a 1 in it

its to do with knowing complements again but its complements of five this time

I imagined before we did this that only complements of ten would be useful

I have an image of ten in two equal parts

I sort of see five’s and zeros going on and on and I feel the importance of the 10, 20, 30, 40 series is important somehow – they’re like barriers or boundaries

I see it as a sort of hole filling exercise – from the six I see 5 of them “falling” on top of the 15 and filling it up to 20, and then the one is all alone

6 + 17

I don’t like 6 add 7, I like 7 add 6, perhaps because 7 is nearer a ten boundary ?

it doesn’t matter which one you do – that’s the commutative rule again

6 and 7 look like 13 to me

I make the 17 up to twenty by using 3 of the six, then the 3 left  goes on top of the twenty

there’s a lot of manipulating going off in here

first  you scan it, you make a decision to make the 17 up to 20, you decide you need 3, you look at the six and take three off it, then you can forget about the first 3 that you’ve just taken off, but  you have to hold the 3 that’s left in your mind  and stick it onto the 20 you’ve just built – wow, there’s a lot of things in there – a lot of decisions, memory and pictures

useful complements to boundary  numbers like 20 and 60 are  the same as the complements to 10

that might not be obvious to little children

23 + 21

place value is fundamental

you have to see the 2’s being in a different sort of group to the 3 and the 1

I scanned it and then I felt like adding 20 on to the 23, which made 40, then I added the last 1 on to make 44

I sort of added the two sets of numbers simultaneously but my mind had sorted them out into the place value set, that’s the twos, and the “bits left over” set which is the  3 and the 1

so there were two parallel columns in my mind even though its written out horizontally

by just scanning it I know that this is an “easy” sort of problem because neither sets of numbers are going to cross a tens boundary so I know I haven’t got to hold much in my head

23 + 28

this looks worse than the last one because I know I’ve got to cross a boundary

I see 8 and 3 make 11, then I  added 40 to get 51

really there’s a lot in here again if you take it all to pieces

I scanned it and I suppose I was comparing what I perceived with my memory banks of tricks  and concepts trying to match something up.  I recognised the 3 and the 8 as being 11, though I think I actually “saw” 8 and 3, not 3 and 8. I knew that I could keep certain groups of numbers separate, the place value thing. Then I was floundering a bit because it didn’t come to me immediately to add on 40, there was a delay, and I was a bit worried about finding the path to the answer. I nearly added on 2 to the 11 and then two more, to make 15  but I knew this was wrong. Still, I nearly did it and the image of 15 momentarily popped into my mind. I was quite shocked

I noticed that though there’s quite a lot of separate things going on before we get to the answer, we only seem to be able to do them two at a time

the way we do things can be sort of binary and linear, but in other ways what we do is like “deal in wholes”

this scanning thing seems very important to me

I think the scanning process is connected with wholeness and a kind of “holistic  sensing” and this “informs” the analytic mind of “the way” to follow to get the answer. This “way” is then put into practice using the analytic binary “mind” that begins operating on the figures or images of the figures

sometimes though, one “sees” the answer immediately without seeming to have “done anything” and even when the “binary mind” is set  working, the “sub answers” still might “pop in” holistically

so I suppose the analytic and the holistic work together in there

some people seem to have a good “feel” for number and operations with numbers

perhaps this is connected with this “holistic sensing, scanning and tapping in to the body of previous experience and insight”

the scanning causes “resonances” with past insights

so in order to become good at adding we should make provision for them to have rich experiences and insights of all these matters we have been talking about – at least

56 + 29

I have to write the numbers down underneath each other

I scanned it again and decided to add 30 to the 56, which was easy and then take 1 away to get 85

I looked at it and just knew that 9 and 6 were 15, then I added 70

I took one off the 6 and gave it to the 29 to make it 30, keeping the 55 in my head, then I knew the answer was 85

I  saw 70, another 10  and a 5, but if you take that to pieces I suppose it was quite complicated really

29 + 59

well, when I see this I can see that its best to call it 30 and 60 and then take 2 off

some people might think that’s not “fair” but it gets the right answer

if you’re taking things off from a ten boundary then that’s complements again isn’t it, but this time you’re coming down rather than going up

it’s still complements that make ten

you’d have to know that if you add something on to change a number to an “easier” one, you’ve got to take whatever it was off again at the end

I suppose that might not be obvious to some children, or at least it might need a lot of practise

it’s an abstraction isn’t it ?

123 + 148

it’s not really any harder if you know all about place value

all the same kinds of thoughts apply

I suppose you really need to know that the 1’s are actually standing for 100’s

yes, its a matter of deciphering meaning again

there are more things to hold in your mind as the numbers get bigger, so I suppose people feel more of a need to write things down

yes, I suppose the individual reaches a point when it  becomes necessary  or at least useful to start writing things down, though I suppose some people can hold more things in their minds than others

I wonder if this is innate or whether it can be improved by practise ?

is there a best way  of writing the working out down?

well, no, because if we help them to scan “sums” and help them to have a good “feel” for number, this implies a variety of ways might be appropriate, not  just one way

I know but I was taught to do adding up in one particular way and it works for me

well yes it might work, but is that all maths means to you then, learning a few techniques so you can use these skills as tool s in other areas like science, or for doing your tax returns?

you’d probably use a calculator anyway

maths can be seen as a creative  vehicle  in its own right can’t it, like painting?

why can’t you see that individuality can be allowed a place in there?

most people don’t like maths and it’s not surprising is it?

it’s our job to try and let people see it as something good to do in its own right

if we want to be good teachers its no good just re-inforcing our own programming is it?

what was good enough for me is not good enough for the children I want to teach

if we work at it and try to see all the issues inside even the simplest looking thing like

2 + 2, and so on like we have been doing, and then provide loads of rich experiences so they can practise the things we think are important, and so get the children to have lots of success and so on at their own level, then that’s got to be good for the children and good for the image of maths hasn’t it?

see this for the results

going down…millionth, billionth, squillionth

Here we go….however just before we begin the descent, I would like to claim that as far as I know, the following kind of representation has not been done before. I stress ‘as far as I know’, so apologies to anyone who has. I may be up for a Nobel Prize…whoa!

Instead of the rod power towers going up, they could of course go down. They’d be subterranean establishments like secret government underground levels where they interrogate aliens and hide their nuclear mission control nodes.

Towers that ‘go down’ are a bit hard to do with real rods unless you had good glue and worked underneath the table, however they can be represented if we use the standard L form for towers layed down flat on a surface then go the other way like this:

one thousandth 10p-3one millionth 10p-6one billionth 10p-9one trillionth10p-12

10 to the minus 12th, that’s how you say it.

The minus sign is a bit upsetting, but just think of it as making the power  towers go down. The other way to think about this is to understand that its a short hand way of writing down the fractions, one thousandth, one millionth etc. i.e. it is one whole one reduced in size by a thousandth or a millionth. Another way is to understand that its one whole divided by a hundred, a thousand or a million. Look, here’s one hundredth:

1hundredth this is the same as 1over1p2 or it can be 10p-2

They’re different ways of writing down the same thing.

Look here,

for millionth you say micro, for example you could say a micrometre – an anthrax spore is about 6 micrometres across.

for billionth you say nano, for example a nanometre, a billionth of a metre – the diameter of a ribosome is about 20 nanometres.

for trillionth you say pico, you could say 6 picometres, 6 trillionths of a metre – an average atom is about 100 picometres in diameter.

Then you get, femto, atto, zepto and yocto.

One yoctometre is 10 raised to the power -24

A squillionth of an inch is half a grain of spacetime.

going up…million billion godzillion

Here we go…

thousand 10 to the power 3

million10 to the power 6

billion10 to the power 9

trillion10 to the power 12


A 3 rod naturally, as THE COMMON DIFFERENCE in this particular staircase is 3

Just for fun here’s the names of some of the other big guys:

quadrillion 10 to the 15th

quintillion   10 to the 18th

sextillion     10  to the 21st power

septillion    10 the 24th

octillion, nonillion, decillion, undecillion, dudecillion, tredecillion, quatuordecillion, quindeciliion, sexdecillion, septendecillion, octodecillion, novemdecillion, vigintilliion…and so on for ever…

Of Latin origin except for:

godzillion  10 to the power of godzilla

fun with powers of 2

Computers work with base 2 because switches can be either switched on or switched off just like your light switches. ON or OFF, that’s 2, so its base two. (We have 10 things on the ends of our two hands so we count in base 10, its as easy as that. If we had 8 fingers like the Martians we’d count in base 8 obviously).

Here is 2 raised to the power 8:

2 to eighth


2 to 8 L 1


2 to the 8th

If you work out 2 x 2 x 2 x 2 x 2 x 2 x 2 x 2 you get 256

THIS IS CALLED ONE BYTE, there’s 8 BITS in a byte. That’s the INDEX, 8 above.

Here’s a typical BYTE:   1 0 1 0 1 1 0 1

Its a number in base 2, where you can only have the numbers 0  (which represents ‘OFF’) and 1 (which represents ‘ON’).

The different columns are similar (in fact isomorphic is the word, I love that word) to our normal (base 10) number system, but every column is worth twice as much as the one before, unlike base 10 where every column is worth 10 times more than the one before.

I just wanted to tell you about multiples of bytes, so here goes:

1 byte is 2 to the power 8

1 kilobyte is 2 to the power 10

1 megabyte is 2 to the power 20

1 gigabyte is 2 to the power 30

1 terabyte is 2 to the power 40

1 petabyte is 2 to the power 50

1 exabyte is 2 to the power 60

1 zettabyte is 2 to the power 70

1 yottabyte is 2 to the power 80

1 yottabyte is  enough memory to store 250 trillion DVD’s


and remember, that’s a pile of 80 crossed red rods if you call the red rod 2. I bet you can’t make one of them… However, is there another way using rods…? I’m not telling…

One of the most powerful computers at the moment is TITAN, built by Cray at Oak Ridge, and it can only store 17.59 terrabytes of information. How pathetic is that? (Got to admit, it’s pretty fast  though….)

However the US government has a computer called DAWN which can simulate the brain of a rat, that’s coming on…. In another 20 years or so, there will be computers that can simulate the brain of a human….that’s SCARY and we’d better WATCH OUT!

heights of towers and titchy little numbers up and to the right…(logarithms and indices)

OK so this is worth three threes, 3 x 3


The ‘answer’ or product is 9

Another way of representing the same meaning is:

3x3 log2

It means 3 raised to the power 2

The height of the tower is 2.

Next its 3 x 3 x 3 followed by  3 x 3 x 3 x 3:


3 x 3 x 3, answer is 27

3x3x3 log3

This means the same, 3 x 3 x 3, 27


3 x 3 x 3 x 3, answer is 81

3x3x3x3 log 4

This means the same, 3 x 3 x 3 x 3,  81

There is another common way of writing these power towers down:

powers of 3-b

The little number is THE HEIGHT OF THE TOWER, called the INDEX

Just as the names of the numbers after ten have unusual names like ‘eleven’ and twelve’, the first two of these have other common names. Numbers raised to the power 2 can be called ‘squared’, i.e. 3 squared, and numbers raised to the power 3 can be called  ‘cubed’. After that its all ‘regular’, they are called something ‘raised to the power something’, such as 3 raised to the power 4 in the last example.

( You can easily make a square using three threes on the flat. Multiply the length of 2 sides together and you get 9, the same as 3 x 3 . You can make a cube of three rods, then if you multiply the 3 sides together you get 3 x 3 x 3 which is 27.

By the way, the square root of 9 is 3, and the cube root of 27 is 3…its all playing in the same ball park).

10 raised to the power 100 is called googol.

The number of atoms in the universe is about 10 raised to the power 79, so googol is far greater than the number of atoms in the whole universe.


powers of 3-b

So the INDICES are the little numbers. Now wait for it,

THEY ARE ALSO THE LOGARITHMS OF THE ANSWER, provided you are talking about the same colour rods, in this case 3 rods or light green:

2 is the LOGARITHM of 9 in BASE 3

3 is the LOGARITHM of 27 in BASE 3

4 is the LOGARITHM of 81 in BASE 3

The main use for these logarithms in the olden days of torture in school was that:


The same is true of indices, and these days this is still useful with very large or small numbers, as in maths, physics and engineering etc.

I’m getting a bit fed up with this now, so just let’s say to finish and for a quick example, 3 squared multiplied by 3 raised to the power 200 is 3 raised to the power 202. As to the answer, I’m too tired to figure it out. Goodbye.

the LOGARITHM is the height of the tower

Logarithms sound bad I know, but they’re not.

Look, this is 10×10

Say, ‘ten cross ten’. The answer is 100 is it not? It is 2 layers high:

10x10 log2

This means the same thing, but we use less rods when the towers get higher. We can turn this one on its side if we like:

10x10 log 2 flat

Now it looks rather like this flat representation:10 power 2

This means 10×10, 10 squared, 10 raised to the power 2, answer is 100


…if you are using orange rods and you call an orange rod 10


The only thing to stress is that the tower must be made of the same colour of rods.

This colour is called the BASE

crossed rods or power towers

Sometimes you are in great danger of either running out of rods or wanting to show how to understand a better way of writing out or showing large numbers. See this:

crossed rods

Put the 5 across the 10. Get used to this, its so useful. Its just another way of showing the same thing. If we agree on it, it works, that’s all.

Here’s another that comes from the ‘real’ world, though you still see it on your flat screen:


This is not two sixes, its six times six, six multiplied by six, its six sixes, its 36.

We have gone UP rather than staying on the flat. We have moved into another dimension. COOL…

The height of our little 6 rods is 2. There are two layers. To use an even cooler way of saying the same thing, so long as we agree, which we do, you can do this:

6 to power 2

This means 6 times 6, 6 multiplied by 6, six sixes or:


Another way of saying this is six squared.

Take a look at googol and googolplex: