My kids used the Dragonbox apps, I just went to look them up and they are know a Kahoots company.
https://dragonbox.com/
Back when my kids were small (they are now 19,19 and 14) they used Big Numbers, Algebra 5+, Algebra 12+, and Elements which were at that time the only ones developed. They are excellent. My husband is a mathematician and he agreed with me at the time.
The 19-year-olds are now in uni, one is studying applied mathematics, and the other design engineering. At this point the 14-year-old is interested in math and electrical engineering, he is also an accomplished musician, and math and musical understanding go hand in hand.