While there isn't a single official link for the entire Math Makes Sense Grade 2 Practice and Homework Book

Unit 3 (Addition & Subtraction): Includes lessons on doubles facts and making 10.

Max scratched his head, then remembered the lesson on addition. 3 horses (4 legs each) = 12 legs; 2 birds (2 legs each) = 4 legs. 12 + 4 = 16. He shouted, "16!" The first door creaked open.

: The curriculum includes varied activities and extension tasks to support both struggling and advanced learners. Critical Perspectives Inefficiency

Because the book is still under active copyright by Pearson, the only legal ways to access the digital version are:

What is Math Makes Sense?