JF Ptak Science Books Quick Post
At first glance this math teaching tool looks a little on the obvious/antique/useless side, but I think that there are some good points to it in helping small children understand the concept of what a number "is" and relating the processes of addition and subtraction to the relationship of "numbers" to "things".
And as the inventor points out
and so on...
This certainly seems more beneficial and utilizable than the current practice in my daughter's third grade class, where a simple subtraction problem is turned into a double addition problem employing a number line, all in the name of teaching the children the concept of "number" and doing away with algorithms. I think that by the third grade, the concept of "number" has been established, though the board of edu-selection might be trying to re-visit a lost point of development somehow.
So with my daughter's class,take the problem 456-345= ______
This is made intoan addition problem, 345+ ____= 456.
The addition problem is turned into a number line, with 345 on the left far end and 456 on the right.
The children are told to add the requisite bits to 345 to get to a "zero unit" for each place value, and then add those for the solution to the problem.
So: 345+5= 350, 350+50=400; 400=50=450; 450+6+456. Add the 5+50+50+6= 111.
In this confusion a stab at the heart of understanding the concept of "number" has beenb made.
A step back from this would be a wise move to make.