Robbie and Alyssa are sitting in their caregiver’s lap when Robbie introduces the birthday theme. He announces, “I got the hat.” Robbie may decide that the orange ring is a good symbol for a birthday hat because it rests on top of his head. The caregiver supports the children’s theme by inviting them to sing the birthday song. Notice what the caregiver does to extend the birthday topic. She asks, “And then will you help Timmy blow his candles out?” Carefully observe how she suggests that the child’s symbol is not sufficient by saying, “Oh, you’ve got to blow harder than that if you want to blow the candle out.” Alyssa says, “I ate all the cake”, and quickly shifts from the birthday theme to reciting her phone number. Alyssa symbolizes the act of reading by holding a book open and looking down at the pages as she recites her phone number. Notice how the caregiver negotiates the children’s introduction to two different classes of numbers: ordinal, counting in sequence, and nominal, reciting phone numbers.