I just had a similar situation come up tonight. My son had one question that referred to "algebra tiles". He maintains that his teacher has never mentioned them. I have never heard of them. There was a drawing (in b&w) of some bars and some squares.

OK, so I type 'algebra tiles' into Google, and up pop a bunch of websites. The first one has an online tool, so I play around with it and end up more confused than when I started.

This link:

[Link: mathbits.com]

helped a bit, but as his picture was just of some unlabeled black and white squares and rectangles, there was a bunch of missing info. All of the tiles seem to be color coded as to positive/negative. The b&w drawing was quite unspecific.

I guess you learn something new every day.

I hope we got the answer right.