You wrote:

> The point of the lesson/activity is to evaluate whether the students understand that 1/8, 0.35 and 50% are comparable things.

It appeared that the teacher, in the 7th grade, was trying to teach probability, and your point about "1/8, 0.35 and 50%" is not
not significantly about probability. Further your point about "1/8, 0.35 and 50%" is too elementary for the 7th grade. Uh, at one time I was in the 6th grade, and the 7th, and even, could one believe, the 8th and do remember some of it!

My 7th grade teacher was quite comfortable giving that little puzzle problem and letting the class spend the whole period on it. It was a good little lesson.

It appears from this thread and some other sources, e.g., from
North Carolina, that probability is too difficult
for most of the K-12 faculty. So, I gave some easy lessons
on how to teach elementary probability.

I've been a student, am well qualified in probability, and
have done a lot of teaching. I know fairly well what the heck
I'm talking about.

Sorry, but that 7th grade teacher was not doing well.

Also the remarks above in this thread -- I tried to be nice
and not mention them -- on "continuous probabilities"
and "fuzzy" need to be flushed: Some probability distributions are continuous, but the 'probabilities' themselves are not. That is, we know in very fine detail just what 'continuous' means and what a 'probability' is, and 'continuous' does not apply to a 'probability'.

Further,
'fuzzy' is from a quite different subject. Saying 'fuzzy' seems
to imply that maybe some probabilities do not really exist;
no, this is a fundamental error, and quite serious. Instead,
with meager assumptions we can assume that probabilities
always exist; the issue, then, can be finding numerical
values for the probabilities, and for that we usually have
to make an 'estimate' and that is mostly in the field
of statistics and usually makes use of at least the
weak law of large numbers. That we have to make an
estimate does not justify 'fuzzy'.

From the OP, I can believe that the 7th grade students
are up to understanding probability but that the OP
is not and is not up to teaching it. Sorry 'bout that.

It appears that the K-12 teachers have been in an echo
chamber far too far from the solid material in US
universities and now are frequently circling their
wagons to defend themselves from attacks on their,
let me pick the right word, incompetence. Instead, the
teachers should learn some probability. I suggest
texts by M. Loeve (long at Berkeley), J. Neveu (from Paris and a Loeve student), K. Chung (long at Stanford), L. Breiman (a Loeve student and long at Berkeley),
or E. Cinlar (long at Princeton)? To read these texts,
start with, say, W. Rudin, 'Principles of Mathematical
Analysis' (at least once used in Harvard's Math 55), the first half of W. Rudin, 'Real and Complex
Analysis', and H. Royden, 'Real Analysis'. Royden was long at Stanford. To read those
books, be a college math major in a good program.

Then we can talk more about probability and how to
teach it. In the meanwhile, if I had a student in
that 7th grade class, I'd insist to the principal that
the class receive some competent instruction in
probability from a different teacher.

Probability is a nice subject, and it is possible to
do a good job with an elementary introduction, but
the OP showed that the content of the teaching
was a mess. E.g., there was "percent probabilities" and "theoretical probability",
and the informed mind boggles. With such teaching,
probability will be several times more difficult than
necessary; with such teaching, the students
are done real harm and later will have to "unlearn what
you have learned". So, the teaching is not just babysitting
but harmful babysitting.

And we pay real estate taxes for such garbage?

Am I making myself more clear?