Houghton Mifflin Journey’s First Grade Unit 3 Crossword Spelling Practice. What a fun way to practice spelling words! For this unit we chose the 6 spelling words, the 2 challenge words, and 4 out of the 8 high-frequency words per unit to keep a consistent 12 spelling words per week. This packet includes 5 crossword puzzles; 1 puzzle for every unit! My first graders love doing these at their Spelling Center! Cute graphs by MyCuteGraphics.com.