You might have noticed that some gas stations occasionally offer specials on unleaded 88 octane gas—also known as E15—which contains 15 percent ethanol. Ethanol is an alcohol that’s derived from corn.

The plus sign (+) means "ADD" in programming and on calculator keyboards. For example, 10 + 7 means 10 added to 7. It is also used as a concatenation symbol for text fields. For example, city + ", " + ...