Just a moment ago, i received a text SMS by my ex-student that i have coached last year asking me the following question: “Which one is counted as Low Melting Point, -108 degree Celsius or 259 degree Celsius?”
It is from this question that i recalled that quite a number of students has problem the “-VE SIGN”.
We know that 5 is bigger than 3, and 259 is bigger than 108. We also know that 4 is bigger than 0.
But it is when we consider the -ve sign that students have issue in their thought process to get the answer.
-5 is lower than 5, -5 is also lower than -2, -500 is lower than -200. Do you get it?
If you don’t, then you might want to start drawing what i call a Temperature Line (Number Line to be exact) as shown below:
(Click for larger view)
We should always start with zero (0) as the 1st point and then all positive value to be on RHS and all the negative value on the LHS. With that, you can easily see that -15 is lower than -5 , and certainly – 598 is lower than – 278.
Hope this simple tip will help those that have problem in visualizing it.
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