In this lesson, you learned how to write subtraction number sentences. In a subtraction number sentence, you find the missing part that joins with the given part to make the whole. Directions. 1. Click to begin. Now you are the teacher! 2. Tell how to write a subtraction number sentence. Draw pictures if you want. Write a subtraction number sentence. Use words like: whole, part, and difference. 3. Circle the number that shows the difference. 4. On page 2, grade your journal entry. 5. Tap the green check to add to your journal.