Easter is tomorrow! And there are a couple of freebies for your elementary-aged child available for the Kindle. Even if you don't have a physical Kindle, these books read well with one of the free Kindle reading apps, which are what I use.
Please note that these books are free as of the time of this posting. Prices can and do change at any time. Closely check for the Kindle Buy price, and not the Prime price.
Puzzlebook: 20 Easter Puzzle Quizzes
The Grabarchuk Family is known for their interactive puzzle books for the Kindle. The colorful quizzes start out easy with one * and work their way up to the hard ***** puzzles. The games are appropriate for children through adults. And based on my experience with a previous puzzle book of theirs, I can verify that the interactive features do work on the Kindle apps.
15 Tangram Puzzles - Easter Edition
The ancient Chinese puzzle of tangram gets an Easter twist in this interactive Kindle book. Arrange the tangram shapes so that they turn into various Easter-themed shapes. All you are given is the black shadow, but answer keys with individual shapes are also included. Also learn how to create your own tangram set from paper, so that you can develop your own puzzles.