Checking Work? How?

I discovered the other day, my students think checking their work means one of two things.  They either glance at it and make sure there is an answer for each and every question, or they want the answer sheet to check against their answers.

It is really my fault that I did not identify the problem before now but I honestly thought they came into high school knowing how to put the solution back into the original problem.

I admit, I assumed they got through elementary and middle school being told to check their work in the normal manner but they haven't, just as if they are not required to show all their work.  The would rather put answers only.  I do not know why.

Since this school year has about two weeks left, its too late to really start working on having them check their work, so next year I plan to tackle it. In the meantime, I am reading up on ways to help my students learn to check their work be it on a test, a quiz, or on the regular assignment.

I ran across a suggestion of breaking the idea of checking work into three levels. The first level is for students to check to make sure they have answered all questions.   This is a good tactic when you run out of time.  The second level requires the student to read the question before looking at the answer to see if it makes sense.  If it doesn't make sense, you check your work.  This helps eliminate simple mistakes.  The final or third level is when students reread and rework the questions. 

I don't usually do any of those levels myself.  I am more into having students take the answer and put it back into the original equation to see if it works out.  I have no problem with them using a calculator to double check the math in this way.  This is the way I was taught to find a mistake.  Once I found an incorrect answer, I then checked the math in each step to so if I did something like 3 x 2 = 5. 

One thing I have done to help them begin the process of checking their work is to have them solve problems on worksheets with answers already there. If the student does the problem correctly, it will yield a letter to write in a blank.  If they do the work correctly, the end saying answers the question at the top.  The down side of doing this is when my students are about half way through a problem, they look at the answer to "find" the proper one.  Unfortunately, they often write the problem down, show some of the work and jump to the answer.  Sometimes they are right, sometimes not.

Next year, I am going to use fewer of those.  I am thinking for the first few weeks, I'll put the answers up on the wall but the answers will be shown in the form with the answer in the original problem so they get used to seeing it in that form.  I suspect its going to result in "Do we have to check our answer?" because I already get the "Do I have to show my work?" and "Do I have to write all that down?".

If you have any suggestions, I'd love to hear from you.  This is one problem I'd love to hear suggestion on. Thank you.  Have a great day.