These are perfect for young children who are learning to count to 100. Older children may find the puzzles too easy or the images too juvenile.
I also recommend for older children, the educational dot-to-dot books by Monica Russo and others by Evan and Lyle Kimble. Fun books for older kids to adult level are the "Greatest Dot to Dot book in the world" of which there are 4 different books in the series.