Are they in CCD? Is the Catholic faith new to them? I ask this to help you answer your question.
I am a homeschooling mom using Catholic curriculumn. I use Seton Home Study which is fully accredited and approved by the church. They have great religion books. I would recommend them because they are set up to do a little each day. setonbooks.com/search.php?subject=Religion&grade=0&userSearchString=&x=21&y=11 setonbooks.com/viewone.php?ToView=P-RL04-21
The 1st link is for what they have available for Kindergarten. It has many coloring and picture books. I believe that we have almost all of them. I have found them at a local Catholic book store. The 2nd link is for the 4th grade religion book. It is set up for a 4 day week with the 5th day being a crossword puzzle or something for review. My kids really like them. They cover the Creed, 10 commandments, sacraments, etc.
Our CCD uses the Faith and Life series. It is very good, but is deliberately set up to where it is above the students reading level since they understand at a higher level than they can read.
Another good thing to get is saint stories for kids. We like Once Upon a Time Saint Stories. love2learn.net/samples/onceupon.htm This has a sample page of the book. We like these because unlike some saint books, these are not overtly graffic in what happens to the saints like when they are martyred.
One important thing, have a Catechism or two and Bibles around your house. Read from the Bible as a family.
When kids ask a question about the Faith, or something comes up (maybe a TV show, news or conversation), look it up in the Catechism and look up the Scriptural references as well. Kids will learn where to go when they have a question.
My personal favorite series for teaching my own kids is the Image of God series put out by Ignatius Press. I have been using it for years, and I think it’s a good balance of traditional doctrine told in a modern form.
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