Today we started with Nana's Chocolate Milk from Dan Meyer. I used it as an introduction and students brainstorm how they might fix the 2nd version. We then went into how we can tell if the ratios in a ratio table are in proportion to one another. I had students record a correct ratio table on a dry erase board, and look at what they noticed that might help us prove that the ratios were in proportion. We were able to identify some misconceptions through our discussion. Then I gave them three additional values and asked them to extend the table. Here is the powerpoint I used...problems borrowed from my other 7th grade teacher :) I think I'd like to change the original ratio table...it had inputs of 5, 10, 15 so students jumped right to the pattern and sometimes didn't look beyond that pattern on their own and I had to suggest other parts to look at.
Finally, we looked at a ratio table that had errors...this was the piece and had them correct and put into their INB.