standard_description: Fluently add and subtract within 20 using mental strategies. (See standard 1.OA.6 for a list of mental strategies.) By end of Grade 2, know from memory all sums of two one-digit numbers.
problem_activity: Anton writes a model that describes the number of tacos his friends eat as a function of the cost of the total tacos. Below is a graph of the model.
[IMG]
Anton writes a second model that describes the total cost of the tacos as a function of the number of tacos his friends eat. Below is a graph of the model.
[IMG]
Label the axes appropriately. Which one makes more sense?
How are these two graphs similar? Different?
How are these two equations similar? Different?


aligns: no