Counting on Frank by Rod Clements
Talk about estimation with the kids. Explain to them that when you estimate, you give a “best guess”. Have several jars with various amounts of objects in them and let the kids estimate the number of items in the jar and then count the items to see whose estimate was closest.
Prehistoric Actual Size by Steve Jenkins and I’m Big by Kate McMullan
Draw an actual dinosaur footprint (I found dimensions for various dinosaur footprints on the internet). Have the children guess how many child-sized feet it would take to fill that footprint. Then have the children remove their shoes (or they can stand inside it if they feel like being close!) and place them inside the footprint. Count how many kids feet it took.
Fish Eyes by Lois Ehlert
Catch diecut fish with paperclips and rods made of rulers, string, and magnets.