One example we used was 65-48, my initial number line looked like the following:
17__(-3)__20___(-5)___25________________(-40)___________________65
<-------------------------------<-----------------------------<---------------------------------<
The arrow indicated the direction we are working, because though you would start with 65 when subtracting 48, the visual line still must read from left to right. So in this example the numbers -40, -5, and -3 all add up to -48 which is the number we're subtracting. Being able to break up the number into clearly visual parts is extremely helpful for new math learners and a great tool for teachers.
A clearer example of this method is shown here:
With a new tool under my elementary education belt, until text time!
photo cred: http://learnzillion.com/lessons/1583-solve-subtraction-problems-using-a-number-line
I enjoyed reading your blog! You explained the math problem process clearly. I thought it was helpful having a picture of what you did to help show how you got your answer. I like your method way better then stacking.
ReplyDeleteNice simple explanation of how to explain the number line method There were about five different ways people solved this in class and is way was the easiest way for me. The traditional way doesn't fully make sense to those who haven't been introduced to many aspects of math. It's important to start with the basics first and introduce more complicated concepts.
ReplyDeleteNice blog!
Your blog gave a great explanation on a simple way to do subtraction. I liked how you used the visual aid to back up your points. Subtraction can be difficult to teach but this way to subtract seemed to be clear to most people. I believe this method should be more widely used.
ReplyDeleteKyra,
ReplyDeleteThe way you described the number line method is so clear and understandable! I agree that not everyone is great at subtraction, I had a difficult time myself as an elementary student. By using a visual aid, as you said, it helps them understand the problem better by putting an image to the problem. This seemed to be the best way to understand how to subtract the numbers in class because the stacking/borrowing method was not clearly taught to some, also if you tried to explain and break down the stackng/borrowing method, it wouldn't completly make sense due to the borrowing of "10's" instead of just a "1". Overall I agree that this is the most beneficial method! Great blog!