Planet 8 begins by looking at making nouns plural. We highly recommend watching our video for this level, as it explains when to make a word plural by adding -es as opposed to just -s.
To summarize, words that end in x, ch, sh, ss, or a single o usually add -es when they become plural.
The word potato had a moment of spelling infamy back in 1992 when former Vice President Dan Quayle encouraged a student to spell its singular form as potatoe instead of potato -- an error based on the Vice President (or whoever made his cue card) knowing the correct spelling of the plural word potatoes but not realizing that in making the word potato plural, both the e and the s had been added. We've included that word in this level so your students won't ever make the same error.