This worksheet clearly explains the 4 spelling rules for adding -er and -est to adjectives and adverbs and provides practice. While the narrative portions may be too advanced for beginners, the simple formulas and examples make it easily understandable even for those just learning comparative and superlative. This worksheet can be used to introduce or review the material. Answer key on 2nd page. This worksheet may be used alone, but was designed in conjunction with a PowerPoint of the same name.