Lonesome-Eight Challenge

[pier4r]

(09-09-2018 10:31 AM)ijabbott Wrote:  So, like the Mexican layout, if you have difficulty doing the subtractions (to obtain the remainders at each step) in your head, you have to do them "out of shot" on a separate bit of paper? The English long division method does the subtractions "in shot".

Yes very likely if the divisor is large for example. In that case I need to do the multiplication on the side and also the subtraction if needed. Now I also see why people put the dividend on the right. A problem I often had is that when I have to go into decimals in theory I have no space left going from left to right (in practice I go under the quotient, as it is written on one line). If the dividend is directly on the right, it doesn't matter as one has space.

[Albert Chan]

(09-09-2018 09:56 AM)pier4r Wrote:  

Code:

10020316 | 124
  10       8  (1st operation)
  100      80  (2nd op)
    11     808 (3rd op)
    111    8080 (4th op)
       0   80809 (5th op)

What is above method called ? Is it Argentina way ? Your own style ?

At first I don't understand why the 3 and the 6 were not pulled down.
I now get it. The numbers are the modulus.

1002 % 124 = 10
10020 % 124 = 100
100203 % 124 = 11
...

It almost look as if everything is done in the head. Amazing !

I like this style, but I would probably write the quotient on top, to line up digits.
Modulus is already in staircase form, so relevant quotient digit can be located by looking up.

[pier4r]

yes I as I said, normally the quotient is written on one line. I wrote on multiple to show how it progresses. And yes the idea is that you do multiplication and subtraction in your head or somewhere else on paper.

I don't know how is it called. Several teachers used it.

And you write only the reminders of the operations. It is like the long division, only you avoid writing the intermediate results.

Actually the more I think about it, the more I like the long division, it is more clear.