https://www.khanacademy.org/math/k-8-grades/cc-fourth-grade-math

Fractions
https://www.khanacademy.org/math/k-8-grades/cc-fourth-grade-math/cc-4th-fractions-topic

Times tables
https://sisalto.oppijailo.fi/pelit/UziFN04HCmIF/index.html