Number line subtraction by Peter Weatherall

[ellylopez1]

Thanks I will show this vid to my kid cause he is a little confused.

[shanadono]

I learned an awesome model today at an interview, of all places. The "as compared to" model for subtraction. Take "7 - 2". This can be read as "7 as compared to 2", which leads to an answer of "they are comparably 5 apart".

It also works for subtracting negatives! "7 - -2" can be read as "7 as compared to -2", which leads to an answer of 9 since 7 and -2 are comparably 9 spaces apart!

So awesome!

[lauren11707]

David, please use this for Calc tomorrow!!!  It's purely brilliant! :D

[Dax192]

I definetely will, dont worry