Edit: it appears that this is not exclusive to ADHD.
Posting this meme stemmed from my own efforts to explain my thought process when doing math and how it is similar to other people with ADHD doing math, while being different from every neurotypical person I'd talked to on the same subject.
While I didn't make the meme itself, instead finding it in my saves and wanting to share, I did accidentally spread misinformation that I had only backed up with personal anecdotal evidence.
I'll leave this up just so people can see the explanation below but this appears to not be ADHD related and just due to different people doing math in their heads differently...
I calculate percentage like this. If 100% is the value, then I know what 10% is, then1%, so I do increments of both until I get to the correct value.
It may sound stupid,but it does help me get a % fast enough.
Thank you! That's pretty neat. I tried 27% of 65
I added two 10% increments (6.5+6.5)... but instead of adding 0.65 (1%) seven more times, I added a 5% increment (6.5/2 = 3.25) and then 2 increments of 1%
So 6.5+6.5+3.25+0.65+0.65 = 17.55
I still had to use a calculator to add those weird numbers (and also check my work), but it does seem really practical for easier numbers. I usually need percentages for pricing (i.e. discounts/tipping), and the percentages are normally in increments of 5%, so that's pretty useful for figuring out a 15% or 75% of something real quick... or at least get me really close (when talking about something like $X.99)
Regardless, I appreciate the head trick!
Edit: I guess I could've done 30% and then subtracted 1% twice; but it's the same issue (of adding weird numbers) with the same outcome anyway. So thanks again!
Another neat trick: X% of Y is equal to Y% of X. That is, in your example, 27% of 65 == 65% of 27. So check and see which combination might provide fewer steps/messy numbers.
13.5 (50% of 27) + 2.7 (10% of 27) + 1.35 (5% of 27) = 17.55
Ahh, that's a really good point! I forget about the "X% of Y = Y% of X"
Honestly, I normally just use a calculator quick (move the decimal twice, multiply and all that jazz) for weird percentages or I want a precise answer.
But I like knowing different ways of thinking about it because it can become easier than using a calculator (with practice). And it's fun, cause I'm a bit of a math nerd