I'm homeschooling two special needs kids in high school who need constant fundamentals and basic algebra practice to help keep their skills up while we attempt more complex problems. So for our Friday math, we use the Maphi app on Apple products. It is great at helping the girls decide how to begin attacking problems with a lot of terms in them and has been key to finally getting the order of operations firmed up in their minds. I'd recommend it for any kid that needs repetition in order to learn the basics. Since it's not a big page of problems it helps my oldest get past her innate fear of math. But it helps keep my youngest from speeding through the problems as fast as she can to get them done - because I say to work problems for thirty minutes instead of to complete a certain number of problems.
I know worksheets have taken a hit in the comments here, but if you do need an endless supply of worksheets I'd also suggest math-aids.com - I went ahead and paid the $20 at the start of the year so that I can use the worksheets for the basis of new lessons. I print one worksheet out with answers and we work it together on the white board. When we're done with a section I'll assign a worksheet of appropriate problems as our version of a test.
For the parents like me who were nervous of teaching their kids the 'right' way, I really love the "Everything you need to ace ^insert subject name here^ in one big fat notebook" series of books. For middle school math we used Everything you need to ace Math I love the way the book breaks things down to short, understandable chapters with good examples. It claims to be "notes borrowed from the smartest kid in class" - but it reads more like a shorthand textbook for teachers. This year we're using the same series book for Chemistry, and it was Crucial to me so that I knew what order might be best for teaching concepts. It's a great roadmap so I can go looking for more specific resources for each chapter.
To be honest I've spent hours worrying about the 'right' this or the 'right' that, and I would tend to say any subject that you teach and they understood was done the 'right' way. We are far too hard on ourselves, and honestly if you keep at it the kids will learn more with you than they would every pick up in school. For a whole year I was half convinced I had wasted a year of my kids' lives...until we had our youngest tested for grade level and she came back with her biggest academic improvement in three years! All that to say...There's no right way to find resources. You've got this, friend.