Composing and Decomposing Numbers

Parents,

Many are seeing your child's math homework and scratching your head in wonder saying, "What is going on?"  The regular math problem of :  7     
                                            + 8
Is now something really unusual, but before we begin, lets review how we usually add.

Well the regular way of adding would have been:

• Add on,  to 7 we would add 8,9,10,11,12,13,14, 15
• Add on our fingers..... ... or dots
• or draw 7 sticks and 8 sticks IIIIIII IIIIIIII
• OR SIMPLY MEMORIZE OUR ADDITION FACTS...really?
• in the past, in our classroom we used adding bears, cubes, ten sticks and hundred plates.
• recent past we used the learn the doubles facts: 1+1, 2+2, 3+3  etc and from there we:
• transition to adding 1 or subtracting 1 when you have a "double plus 1 such as 4+5" 
• the terms you learned and I of ; "borrowing, carrying and recently regrouping", have been layer aside.

Along with lots of "drill and kill" handouts, we are assuming that your child will add and subtract so much that they will learn to add, efficiently, quickly and accurately by 3rd grade.

It's not working for all our children...

A new method called constructing and deconstructing a problem is now the "new" method of teaching addition and subtraction.  In a nutshell:

Let's go back and add 7+8

1. first we switch the numbers around to 8+7
2. then we make 8 into a 10, how by knowing how to "make a ten", we take 2 from 7 and that leaves us 5
3.     8 +  2  +  5  
4.      10 +  5  =  15     
5. Seems like a lot, but research shows that 2nd graders grasp this concept with ease.  

Want try another?

Add 6+8

1. first we switch the numbers around to 8+6
2. then we make 8 into a 10, how by knowing how to "make a ten", we take 2 from 6 and that leaves us 4
3.     8 +  2  +  4  
4.      10 +  4  =  14    

Parents, in order for this to work we need to practice making "10's"

1+9 = 10,  2+8= 10,  3+7= 10, 4+6= 10, 5+5= 10, 6+4= 10, 7+3= 10, 8+2= 10, 9+1= 10

I am currently looking for  links that further explain constructing and deconstructing  math problems and I will post them later...

Mr. Fierros