Eight pairs of words, one ordinary noun and one special name in each: boy and ben, dog and rex, day and monday, city and miami, cat and mittens. The child circles the proper noun and writes it on the line with a capital letter.
Every word is printed in lowercase, and that is the clever part. The capital is exactly what is missing, so a child cannot spot the proper noun by its first letter and has to think about what the word means instead. Writing it again with a capital then puts the rule straight into their hand.
The pairs cover people, pets, a city, a day and a month, so the page lines up with the capital letters first graders are learning for names and dates at the same time.