There is a game called dragonbox algebra which I'm currently working through with my son and is an absolutely fantastic approach to this problem. Sadly its now part of a horrendous subscription service and is hard to access. I find it really sad that we've had computers for decades and there are so few good maths games like this.
As a senior in high school, I devoured this game in elementary school and got way better at math than my peers. Now taking differential equations and multivariable calculus through our college in the high school (CHS) program. When I looked for it out of curiosity I was sad to see it transformed into a subscription service.
