New percentage calculation at work

I have a love for numbers. My guy does, too. We are math nerds.

I recently had to do an online course at work. You need to pass a final exam at the end of this course to get credit for enduring it. The course is roughly eight hours in length. Doing a final exam is painful.

You need 90% to pass the test. I ended up with exactly that percentage... or so I thought.

When I got to the very end of the test, it said that I got 9 out of 10 questions answered correctly. The percentage calculated was 89.88%. What?!

I asked the person responsible for creating the course a question on how this percentage is calculated. She admitted that something was odd. I managed to contact the training support group to get credited for taking this course.

I have never seen a weird percentage calculation like what I got. I told my guy this issue and he laughed.

"It doesn't surprise me that you'd be outraged about the calculation. It's what I love about you," he reminded me.
"You're sweet. You'd react the same way," I replied.
"That's true. We love math."

We do.