I've always thought of these as "Wayside School" problems, because I first encountered them in the children's book, Sideways Arithmetic From Wayside School by Louis Sachar. I highly recommend it for any child who is into puzzles. I really enjoyed how the book deconstructed the format of tests and quizzes that I was so familiar with at the time. My favorite section was the sideways math, where words are added or multiplied and you had to deduce the values of the letters. E.g.,

      D O G
    x   A D
    _______
    
      D O G
    A D O
    _______
    
    A G O G

Maybe children don't learn to do arithmetic like this anymore and this section will be utterly impenetrable to them.