Answer: Hello!
the problems are wrong:
in the first problem, you have 38 rocks, and you can separate them into groups of 10 or in single rocks.
You have 4 options to do it:
0 groups of 10, and 38 single rocks.
1 group of ten and (38 - 19) = 28 single rocks
(this is 10 rocks in the group of then + 28 single rocks = 38 total rocks)
2 groups of ten and (38 - 2*10) = 18 single rocks
3 groups of ten and (38 - 3*10) = 8 single rocks
and you can't form more groups of tens because you only have 8 single rocks left at this point.
in the second problem, the case is the same, now you have 30 pieces of felt and you can divide them into groups of 10 or in single pieces.
then the possible options are:
0 groups of ten and 30 single pieces
1 group of ten and (30 - 10) = 20 single pieces
2 groups of ten and (30 - 2*10) = 10 single pieces
3 groups of ten and (30 - 3*10) = 0 single pieces
in the third problem you need to write, similarly as i did, why you organized the rocks or the pieces as you did.
