Whenever I can find a memory trick that helps students get something straight, I use it. Students needs to remember so many things in algebra, so whatever help we can give them is well appreciated.
So recently I stumbled upon a memory trick that helps students tell which of two numbers is greater and which is less.
You might be thinking: greater and less?! Why would any student have trouble with that? Well, before students hit negative numbers and absolute value, there is generally little trouble. The greater numbers are the larger numbers, the lesser numbers are the smaller numbers. And kids basically know what we mean by larger and smaller whole numbers, when they are dealing with positive numbers and zero.
But when students encounter negative numbers, some things change.
While 10 > 5, – 10 IS not > – 5. Instead: – 10 < – 5.
As if that were not enough, absolute vale comes along and makes things still more confusing, since it takes the value of any number and makes it positive. So now:
abs. value of – 10 > abs. value of – 5