[Blindmath] abacus dilema

Lewicki, Maureen mlewicki at bcsd.neric.org
Sun Oct 23 21:37:55 UTC 2011


Good day, I hope someone can help me with an abacus question. NYS requires that blind students use it instead of a calculator on their tests, therefore, we still have to teach it. 

I use the counting method for solving problems(just basically eliminates, I think the need to memorise secrets, etc.
Here is the problem:

I fear embarassing myself, but I rally need help! The prob lem we got stuck on was 1500/60.
 
My question is really two fold.
 
Setting the 60 on the far left, and setting the 1500 on the right, on the proper place value rods. The quotient is set just to the left of the dividend so  we got an answer of 250.  The rods read this way: 2 5 0 0 0, which means that the ones and 10's columns reflect no remainder. The answer, should leave two rods empty if there is no remainder, so since there are three rods empty, the student assumed the answer was 250 instead of 25.
 
It is the only time I have ever seen this happen! I must be doing something wrong, but I have tried the problem dozens of times, and get the same answer.
 
The Counting method book does not go into two digit numbers dividing three or more digits. Could it be that setting the answer next to  the divisor breaks down with 2 digit divisors?
 
This weekend, I tried setting the problems in a bit of a differerent way, according to a website for chinese abacus.
 
It goes like this:
 
60 is set on the far left. leaving an empty rod, the dividend is placed next, on the left side. The Quotient is set on the right, in the correct value rods.
 
Hence, it reads: 6 0 0 1 5 0 0 0 0 0 0 0 0 2 5.
 Here the answer reads as 25.
 
The problem here is that there is no room for remainders, so perhaps it has to be set to the right of the  150?
 
I have packed this email with too much info! Neverthelss, do you think you could help me? My student needs my help, and I am not sure how to advise her. Thanks so much. 
 
 



Maureen Murphy Lewicki
Teacher of Visually Impaired
Bethlehem Central Schools
(518)439-7681
"When we do the best that we can, we never know what miracle is wrought in our life, or in the life of another." Helen Keller
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