So, I'm a mathematics tutor, and I always run into this mental block that students have: they don't seem to understand what "in terms of" means. Also, the phrase "in terms of" is so useful, and it kind of frustrates me when student don't understand it.
EDIT: Let me explain why I think it is so useful. Sometimes, when I am working with a word problem, we will define a variable to be something like "x=number of apples" or "y=cost of toaster oven". Then to help set up an equation to work through the word problem, I will ask them to tell me what the price of 5 toaster ovens in terms of
y. Sometimes I can work around this phrase, but sometimes I just really wish I could use it. (I guess I could just say "the answer depends on
x", but that kind of has the same set of problems.)
Here's two examples:
Bobby buys 20 apples for \$15 and eats
x apples. He sells the rest for \$2 each. (1) How much money does he make total? Write your answer in terms of
x. (2) How many apples can Bobby eat but still make a profit?
Solve the following equation for
y in terms of
Now while it is fairly easy to get a student to solve such problems, so many students just don't seem to understand the concept of "in terms of". Since it is such an important concept (it is essentially precursor to functions) I really want to convey some kind of understanding.
Does anyone have any good ideas and advice for explaining this or working around the use of the phrase?