(1) Cranmer abacus-adding by 10-easy rules – YouTube
https://www.youtube.com/watch?v=lWYOPshaI1M
Educational Services for Blind/Low Vision -Specialized Instruction in Technology/Braille/Nemeth and other Blind skills
https://www.youtube.com/watch?v=lWYOPshaI1M
https://www.youtube.com/watch?v=M9XVJkQ6gM0
https://www.youtube.com/watch?v=Oz4--cxfeTo
https://www.youtube.com/watch?v=68DYaR89qoM
https://www.youtube.com/watch?v=vVwlltrhTG0
https://www.youtube.com/watch?v=vVwlltrhTG0
https://www.youtube.com/watch?v=KHkMEvHKVgs
https://www.youtube.com/watch?v=MnQmPvEwzFo
https://www.youtube.com/watch?v=OG7gNWzZHhg
https://www.youtube.com/watch?v=WJZv5WG9PJs