Here are a few of my thoughts about your post. I know you probably don't care...but I will give them anyway. I am a math teacher and regarding your statement:
"I had a conference with the idiots at the school today and I have been told that there is very very little chance that these kids can pass. I am going to try anyway of course. My question is this...I have only 4 weeks or so until school is out ( I know, why didn't someone mention that they needed help a little earlier right) anyway..."
Do you think the people at the school are "idiots" because of (1) they said that there is very very little chance that these kids can pass or (2) because they have "failed" to get these kids to pass?
I ask the question because I too have students (with four weeks of school left) that have no chance of passing some of my classes. I have repeatedly been in contact with their parents, the students, the counselors, and whoever else would listen to get them to come in and get help. They failed to do so and now...regardless of what they do...they cannot pass my class.
Also, I have students who are on the border of passing (and have been so for quite some time) who are just NOW seeking help when I have been on them to get help for MONTHS. Somehow I am supposed to see their "efforts" in these final weeks, have pity on them, and "give" them the grade they think they deserve. Just last week I received a phone call from a tutor. One of my students is JUST NOW seeking a tutor (again...with four weeks of school left) despite my pleas to the parents for their child to get help months ago. I was asked if the student had any chance of passing. I simply said "no". That doesn't make me an idiot...it's just the facts of the matter.
In regards to the math worksheets. If it is 3rd grade math then a worksheet should not be difficult to make on your own. However, I am sure that you have searched the web but just in case you have missed the following site...it allows to you generate your own math worksheets.
http://www.superkids.com/aweb/tools/math/
I am not sure what the third graders do in math (I teach High School) but here is another site with basic operations:
http://www.lizardpoint.com/math/mathsheet.html
And another with more complex worksheets:
http://www.aplusmath.com/Worksheets/index.html
Also, there is a site that has virtual manipulatives for all grades. A manipulative is just a fancy word for using objects to "see" a math concept. It may or may not be helpful. The site is:
http://nlvm.usu.edu/en/nav/vlibrary.html
Don't know if any will be helpful but you can check them out.