SOLUTION: Describe and correct the error in writing an expression for the situation. Number of pages of a 5 page article left to read if you've read p pages. Expression: p-5

Algebra ->  Expressions-with-variables -> SOLUTION: Describe and correct the error in writing an expression for the situation. Number of pages of a 5 page article left to read if you've read p pages. Expression: p-5      Log On


   

Question 1154484: Describe and correct the error in writing an expression for the situation.
Number of pages of a 5 page article left to read if you've read p pages.
Expression: p-5
Answer by greenestamps(13208) About Me  (Show Source):
You can put this solution on YOUR website!


To find the number of pages left, you need to start with the number you started with (5) and subtract the number you have read (p).

correct expression: 5-p

Note this is a common problem with some beginning algebra students who try to convert the written expression into an algebraic expression by listening literally to the words instead of paying attention to what the words mean.

"5 more than 3" is, literally, 3+5, because the words say you are starting with the 3 and adding the 5. However, with addition, "5+3" is the same as "3+5"

But with subtraction you need to have the numbers in the right order.

"2 less than 7" means you are starting with the 7 and subtracting the 2. So you can't just listen to the words in the order you hear them and write "2-7"; the correct expression is "7-2".