Texas Instruments has both apps free (normally $30 a piece) until 4/30
https://apps.apple.com/us/app/ti-nspire/id590823242
https://apps.apple.com/us/app/ti-nspire-cas/id545351700
GraphNCalc83 ($5.99) also free
https://apps.apple.com/us/app/graphncalc83/id744882019
https://apps.apple.com/us/app/ti-nspire/id590823242
https://apps.apple.com/us/app/ti-nspire-cas/id545351700
GraphNCalc83 ($5.99) also free
https://apps.apple.com/us/app/graphncalc83/id744882019