Fair Bear Share - I love all the MathStart Books by Stuart Murphy! This one is a great one to talk about place value.
Two of Everything - I like using this book for math and writing. This cute little couple gets a large magical pot that doubles anything you put inside. For math you can use it to talk about the concept of doubling and double facts. For writing you can have students write about what they would put inside the pot.
Captain Invincible and the Space Shapes - This is a fun story to read when you're learning about 3D shapes.
Full House - This is a great book to read to introduce fractions.
Check out all the other picture books for math!