Good websites for math

Due to the cultural celebration beginning at school tomorrow, today is really the last day this week I will be teaching, so I made the majority of work, iPad based. 
In period 1 we've been studying scientific notation.  The students went to http://janus.astro.umd.edu/astro/scinote/  It allows the student to do practice problems before taking the quiz.  I had the students do 10 practice conversion problems before they took the quiz.  On Monday, they will do practice multiplication and division problems using scientific notation before they take the quiz.
In period 2 we've been simplifying, multiplying and dividing rational numbers.  We used this website: http://www.regentsprep.org/Regents/math/algtrig/ATO2/indexATO2.htm to practice these types of problems.  The lessons and practice sections do work on the iPad.  I enjoyed it because the students could do the problems and then check their work.  If they got stuck they could go to the solution and check out how the problem was done step by step.  It gave them some guidance and allowed them to be independent.  I did not see any students go to the solutions and just copy down the answers.
For periods 4 and 5 They will be going to  http://www.mathguide.com/lessons/SurfaceArea.html
to learn more about Surface area.  It comes with a lovely explanation and practice problems afterwards. 
I printed QR codes on paper, put directions under the codes and had the students use the iPads to read the codes so they knew what to do and the code sent them directly to the website.  I did not spend time trying to have them type it in.
I am using these activities to engage them and to monitor their understanding of the materials.  I am glad to find sites that work on the iPad. 
Tomorrow I'll be writing on three math apps I downloaded that I plan to try tonight.  I'll let you know how they work.

Idea for the last week of school and today's exploration.

I am about 4 to 5 weeks out from the end of school where I am.  The last week of school, we don't do much so I am thinking of running a project that will be cross curricular and should be fun. I was reading the back of a VHS tape and there was a project listed called The Math Trail. The students are to use concepts from the math curriculum and create books of problems based on objects and events in their community.  For instance, students might create problems concerning how much heating oil is held in their tank and then write a problem on how much it would cost to fill.  Students would be using math and either ibooks author or some other book making publication. They could take pictures of the items, add arrows, etc. They possibly could add a voice over.  I am going to spend the next few days working up the parameters on it.
Today I had my 9th graders use their iPads to research how scientific notation is used in real life. They found two real life examples and posted them on the board (smart board).  They came up with some really good examples.  Some were the speed of light, government debt, size of a virus, size of the space inside a computer chip, a mole etc.  The kids needed experience searching for information and they also needed to discover how scientific notation is used in real life.