I used The Hungry Catepillar lesson from this link.

https://www.illustrativemathematics.org/content-standards/tasks/1150

However I did an extension off this lesson using this resource to allow teachers to work on the skills of addition, the precise language of tens and some extra ones, and seeing groups of ten.

This activity is a great way to include Language Arts along with Mathematics. Using The Very Hungry Catepillar, we used based-ten blocks to place onto a ten frames. Each time the catepillar eats something, we add to the ten frame. At the end of the story, we look at how much the catepillar has eaten. However, I took this activity a step further to continue strengthening the use of addition. Students and I then had a variety of situations at the end of the story where the catepillar ate 4 more leaves. The students then add four more, either in a group of 4 or counting out 4 individual items. We then look again at using our language of, "I have a 3 groups of ten and 4 extra ones."

Challenges with this lesson is making sure the students have added a cube onto their ten frame for each item they ate. As well, students would have to also understand how to use a ten frame before the start of the lesson. As well, if you are working to be precise with the language of tens and extra ones, you want to nudge your students to use this language. You will want to model this multiple times.