Translation of álgebra

for a minute I blamed the burger that I had eaten at the duty free back in Cancun, but thinking a little further I recalled eating street food the night earlier, as it was Mexican independence day.
The writer describes this situation by putting the persons into a natural environment. On one side there was no shade and there weren't any trees, he says. This description can be interpreted.
Thanks for the tip: We will add a lesson on colours! About the topical lessons around the home: Do you have specific words that you think should be added? It will take a while until we upload the new version.