This phonics workbook fits all our criteria: systematic phonics and spelling rules, exercises that force children to think through the spelling of a word and comprehend what they are reading, and simple, non-distracting graphics. Book 6 deals with -ar , -or , -er , -ir , -ur , wor- , war- , -igh , -oo- , -ea , -ie , -o Sonlight resource: https://www.sonlight.com/products/explode-the-code-6