The Adventure Series (K-5th grade) Sales The Adventure Series (K-5th grade) The Frontier Series (6th-8th grade) The Horizon Series (9th-12th grade) Kindergarten from $19.99 sale View Options 1st Grade from $19.99 sale View Options 2nd Grade from $24.99 sale View Options 3rd Grade from $29.99 sale View Options 4th Grade from $29.99 sale View Options 5th-6th Grade from $39.99 sale View Options