Last week in my Mathematics for elementary teachers, we learned about addition and story problems. We also learned about two-digit addition, using algorithms. When I hear the term "algorithm", it freaks me out, I think of this long, drawn out equation that's going to take me 15 steps to solve. But that's not it at all. I learned that an algorithm is just another word for method. The are 4 different algortihms for addition that I learned.
The first being visual. The concept of addition, with carrying, can be shown visually by using Base Ten Blocks.
The second, is Expanded Notation. Expanded notation is basically just writing out the problem with words. For example:
13
+24
I would write that as: 1 ten and 3 ones
+2 tens and 4 ones
Which equals: 3 tens and 7 ones
After this step, I would write this problem:
3x10 + 7x1=
30 + 7= 37
Another algorithm for addition, is called Standard Algorithm, which is the long way to do the shortcut.
For example: 15
+46
So first, I would add 5+6, which equals 11. And write it like this:
15
+46
11=9+6
Then, I would take the next set of numbers and add, but since the next set of number are in the "tens" place value, I would write it as 10+40, which equals 50, and I would write it the same way as in the last step:
15
+46
11=5+6
50=10+40
Then, I would just add 11+50, to get my answer of 61.
15
+46
11=5+6
50=10+40
61
The last algorith, is called Standard Algorithm. Which is just doing addition the "easy" way, no steps just taking 14+21= 35. Plain and simple.
I have provided a link to a website that will help children in doing addition.
http://www.dositey.com/addsub/add5a.html
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