Numbers & Operations in Base 10 Subtraction

Subtraction Mistake

What’s the mistake? Why is it tempting?

Thanks to Christopher Danielson for this submission. His blog. His twitter.

Elementary School Numbers & Operations in Base 10 Place Value Subtraction

Subtraction Algorithms

Let’s have a good old fashioned brawl: is there a mistake here or not?

This submission comes from Chris Hunter, who blogs at Reflections in the Why.