What tires size can I run?

https://preview.redd.it/6df8730qb0ud1.jpg?width=3024&format=pjpg&auto=webp&s=2a66f72ecc51cc38ed304beff0af32f01f746d71

I bought this sick 87 warrior and was wondering if I could run 21x7-10's on this, the current front wheels are 21x8-10, I just don't know what the different numbers mean.