Long before there were table computers or even computers at all, students did their lessons on slate tablets. These writing tablets were made of slate and the children did their sums with chalk. This vintage learning materials image even comes equipped with some numbers already drawn on it.
I love it when I find vintage materials like 1890 Baby’s Annual Pictures and Stories for Little People. It was published oh so long ago that it is now completely in the public domain. It’s too bad the original artist(s) weren’t identified but that is why this book falls under the 120 years post publication aspect of copyright law.
This image is copyright free and in the public domain anywhere that extends copyrights 70 years after death or at least 120 years after publication when the original illustrator is unknown.