Keep practising your written methods for addition, subtraction, multiplication and division. Use the videos to help you.

Subtraction
https://www.youtube.com/watch?v=Y6M89-6106I

Addition
https://www.youtube.com/watch?v=mAvuom42NyY

Multiplication
https://www.youtube.com/watch?v=FJ5qLWP3Fqo&t=13s (Short multiplication)
https://www.youtube.com/watch?v=RVYwunbpMHA&t=386s (Long multiplication)

Division
https://www.youtube.com/watch?v=KGMf314LUc0