This math chapter workbook on "Addition and Subtraction Facts to 20," has extensive practice for kids to add and subtract numbers within 20. Kids will learn about the relationship between addition and subtraction, such as the facts families pages. Encouraging mental math strategies and introducing simple word problems are included for contextual understanding. For the problem "8 + 5," students can use a number line to start at 8 and move forward 5 spaces to reach 13. For "14 - 6," they might use counters, starting with 14 and removing 6 to see the remainder. These engaging activities build familiarity with number relationships and strengthen mental math skills.