Here are links to video tutorials that @adaubs91] and I made to help pupils learning to use concrete equipment as they get to grips with formal methods for addition and subtraction. These videos are aimed primarily at Lower KS2 but could also be used with pupils who need to work within the concrete stage of formal methods for calculation. You can find all of the Maths tutorials I have created on YouTube on the EducatingHolmes channel. There, you can also find links to other playlists I have created collating a range of videos that I have found useful with my classes. If there are other videos that you recommend using, please let me know so I can can check them out and add them to the playlists!