Saxon's Math Intermediate 3 is a perfect transition into Saxon Math 5/4!
This is geared towards 3rd and 4th graders
Incremental lessons provide daily practice and assessment; mathematical concepts are taught through informative lessons, diagrams, interactive activities, and investigations that build critical thinking as well as real-world problem solving skills. Saxon Intermediate 3 includes 11 sections, 110 lessons and 11 "investigation" activities.

Textbook lessons are divided into three sections. The first section is "power-up practice," which covers basic fact and mental math exercises which improve speed, accuracy, the ability to do mental math, and the ability to solve complicated problems. The second part of the lesson is the "New Concept," which introduces a new math concept through examples, and provides a chance for students to solve similar problems. Thirdly, the "Written Practice" section reviews previously taught concepts. One "Investigation" per session is included; "Investigations" are variations of the daily lesson and often involve activities that take up an entire class.