This A3 size book should be used in conjunction with the four big books in the THRASS 500 SERIES (T-27 – T-30) and the PHONEME-GRAPHEME BIG BOOK (T-21). In the 380 BIG BOOK each word is segmented into graphemes. Use this book to teach classes or groups how to blend and segment the phonemes in the 380 Essential High Frequency Words and to name the letter or letters in the graphemes.