Gifted Issues Discussion homepage Forums Learning Environments What grade level is this math problem?

DD did this sort of thing sometime between 4th and 6th grade.

Common Core, however, is now tethering it as a 6th grade skill.

For instance, IXL considers 2w – 5 = 3 to be a grade 8 algebra problem. ??

Ah, but CC does say: "Reason about and solve one-variable equations and inequalities" for 6th grade

I think that's anchored to the sixth grade standard:

CCSS.MATH.CONTENT.6.EE.B.7
Solve real-world and mathematical problems by writing and solving equations of the form x + p = q and px = q for cases in which p, q
and x are all nonnegative rational numbers.

5th grade "GT" math which is supposed to be 6th grade "regular" math. That was the case pre-CC as my oldest covered it 8+ years ago. I wouldn't place too much faith in commercial online programs - in my limited experience, many of these programs are not as high level as they claim.

DD is in 5th grade GT math, so this appears to be appropriate. I was curious because I certainly do not remember solving equations like this at this age, though a straight-ahead area problem (find area of various shapes with standard measurements given) would have been on the agenda. I'm pretty rusty on how these things are sequenced.

I just showed it to DD10 who did said that she learned how to do this during the AOPS Pre-Algebra class which she took last year. Knowing how to do this by the end of 6th grade sounds about right given that the AoPS class describes itself ( or used to before Common Core) as an adequate 6th curriculum.

I've seen that sort of problem in the Singapore math books somewhere before the 6th grade level (though I'm not sure if it was with a trapezoid). I've definitely seen problems like that (with trapezoids) in various geometry books.

Interestingly, my DD was using an online application called First in Math in 1st and 2nd grade through her school. It was pretty good because the 'higher stuff' was open too - it held her attention until she found that 'Grand Master' was as high as one could go LOL

By the end of the second term of 2nd grade she had completed the 4th grade stuff there. One of the area and perimeter exercises involved working out the lengths of the sides of a rectangle with a perimeter of say x and an area of say y. I was impressed because pretty well the same reasoning lies behind the factorization of simple quadratics.

The school stopped that and we discovered AoPS but I have to say my DD enjoyed that app for a while. It really helped her with her fluency and mental arithmetic too.

The formula for a trapezoid, if you understand the angles don't matter, is very easy to derive visually. Like in a cut and paste common core number sense kind of way. If it's symmetrical you fit the left triangle into the space above the right triangle and get a rectangle that is the length of the short side plus another rectangle that's half the difference in the lengths. The area of this trapezoid is the same as any other one with the same bases, so it doesn't really have to be algebra at all. It's like starter geometry. I don't remember the formulas from school and just thought about the idea and then double checked with Google that I know what a trapezoid was. It looks harder than it is, until you draw it.