(16) Cranmer Abacus-subtract by 3-learn the rules – YouTube
https://www.youtube.com/watch?v=Oz4--cxfeTo
Educational Services for Blind/Low Vision -Specialized Instruction in Technology/Braille/Nemeth and other Blind skills
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=KHkMEvHKVgs
https://www.youtube.com/watch?v=MnQmPvEwzFo
https://www.youtube.com/watch?v=OG7gNWzZHhg
https://www.youtube.com/watch?v=WJZv5WG9PJs
https://www.youtube.com/watch?v=NpYWnuGmChM
https://www.youtube.com/watch?v=0vcYF7iuBM8
https://www.youtube.com/watch?v=Xe31vCLg8gI