Counting

In the car to daycare, Z started to count. He went from one to one hundred, with me only prompting a little.
"38, 39...."
"what comes after 3"
quietly under breath "1,2,3,4"
"40, 41, 42 --- 48, 49......"
"what comes after 4"
quietly under breath "1,2,3,4,5"

"50, 51, 52 --- 58, 59" then quietly under breath "1,2,3,4,5,6", then "60, 61 ---"
He went the rest of the way on his own. and got to 100 as I was pulling into the parking lot.