Number sentence is an equation explained using words a six year old understands. Children use counters all the time. Ever played air hockey? I'm not sure how that would be confusing. A number story is a word problem.
I wonder if it'd be possible that this might have a positive effect in decreasing the gap between men and women in science related fields. Perhaps if we told boys and girls they were doing well with equations they'd grow up to be more comfortable with them. Instead of "I'm not good at equations and never have been and those sound hard" (since they only started using the word with tougher mathematics or maybe never at all), they could think "Equations? Psh, I've been working them over since I was in grade one".
Just an idea.
Air hockey doesn't use "counters" it uses a scoreboard or score keeper.
Number sentence is not what these are called. We're teaching children the wrong things. Now they have to learn the concept twice. Once wrongly, the second time correctly. It's objectively the wrong way to teach.
Is it? I'm fairly certain that teaching is one of the most difficult things that we try to do, and that almost everything I've ever learned has be taught 'the wrong way' and then corrected later. But then, I have a degree in physics, and everything I've been taught about physics has either been wrong or is open to being made wrong. I was explicitly told as a freshmen "nothing we'll teach you in this class is true."
It doesn't matter what those are called. All that matters is how they work.
If I called aerodynamic lift "flying power" and gravity "flying power" and I asked you to calculate the "flying power" of an aerodynamic body on another planet?
You might be able to sort it out as an 18 year old Physic freshman once you learned some context...maybe by your 3rd year in, but a 6 year old being introduced to this stuff for the first time?
It's a terrible way to teach somebody. It's like a Machiavellian approach to pedagogy: confuse and isolate the students so that only the best rise to the top.
But I'm totally with you about teaching children that these are equations. I wouldn't be surprised if this curriculum or whatever was built by someone not comfortable with the word equation themselves, for whatever reason.