It always makes me happy to come across a website that offers quality educational resources for free, a huge thank you to the creators of one such gem - Math Games. Filled with games and worksheets, this website is a go-to resource to develop your kiddo's budding math skills. You can search for resources by grade, they are available from Pre K to Grade 8. Another option is to search resources by skill; you will find some not-so-easily resources here along with regular ones:
Addition
Algebra
Comparison
Decimals
Division
Measurement
Estimation
Graphing and many, many more...
Don't forget to check out the worksheets section when you visit the website. I hope you make good use of this website: