This post has a free printable for students to practice writing tallies to seven, as there are seven ducks in this story.
Quack and Count by Keith Baker is a book about seven ducks and is really several pages of pictures of the seven ducks doing two different things. So I made Free Tallies to Seven Printable. It makes an excellent introduction to the complements of 7 for young children learning math facts. The double facts are fairly easily learned (1+1, 2+2) but the different ways to make seven may need to be taught. By discussing the pictures of the ducks in this book of all two-page spreads, the different complements can be determined. When one duck slides into the water and six watch, the math fact 1 + 6 = 7 could be written.
Children at this math stage are most likely also learning about tallies. Teachers have children tally to help them learn to conserve number and not have to recount the first part of a math sentence. A child who counts out 3 in a math fact 3 + 1 = 4 has not learned to conserve number and is just counting out the math problem. Tallies also help children learn to subitize or to perceive at a glance the how many for different numbers. This helps streamline math thinking and helps children complete math problems more quickly. Subitizing also depends on the arrangement of the objects, and tallies are always presented in the same way. So my free PDF today is about using tallies to find the complements of seven. It is 10 pages and free.