Simple, yet baffling - please help

I am knitting up the ‘Cotton Candy Dress’ designed by Celeste Pinheiro. The next row in the pattern says:

Dec 39 sts evenly across 82 sts.
Simple, right?

There are 121 stitches in total on my needle.
So…how do I evenly dec 39 sts over the ‘middle’ 82 sts?
I figure the middle because the dec are for the waiste of the dress.

I thought about something like (it was around 6:30am this morning and I am not a morning persion - this may explain why it is baffling me): k20, (k2tog, k1) 27 times, k20

Is this proper? Is there a better way???

Not the ‘middle 82 sts’, but decrease them evenly spaced, which is all across the row. If you just dec only over the middle sts they’ll be bunched up. You need to get rid of 1/3 of them - you’d need to k2 k2tog, then k1 k2tog to the last 4 sts and k2tog k2 I think (or maybe to the last 3 sts and k2tog, k1).

Thank you so much.
I read the pattern wrong.
It actually says: dec 39 sts evenly across row. (82 sts).
So I will do
k3, k2tog, [k1, k2tog] 37 times (or to last 5 sts), k2tog, k3

that works, right?
the math I used: 3+2+111 (111=37*3) +2+3 = 121sts

by the way, this pattern can be found on freepatterns dot com

it worked ! it worked ! it worked!
Thank you so much for demistifying for me!

That may come out okay, it’s fine if it’s off a little.