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My engineering brain says it’s 3.25.
4% is ~ 5%. 10% of 75 is 7.5. To get the 5% I have to divide it by 2, so 4% of 75 is close to 3.25. I will have to multiply it with some safety coefficient at the end, so the exact value doesn’t matter.
Mine brain just does 0.75 × 4.
Thought process was…
- Get 1% = 0.75
- Double it = 1.5
- Double it = 3
I’m confused by this statement, the answer is 3. Why do all these extra steps for a wrong answer?
It’s not wrong, it’s close enough. And the point it works with more numbers and more type of calculation. Let’s calculate 4% of 1243. That’s the same as 1243% of 4, right, much easier to calculate by simply changing the 2 numbers… While my method is the same, by simply rounding everything.
And in engineering you always multiply/divide your results by a 1.5 or 1.25 safety factor, depending on situation. So you don’t have to calculate exact results, just close enough. E.g. G is always 10m/s2. π is only 3.14, the other digits doesn’t matter.
That’s the stupidest shit I have heard today. You should feel ashamed if you really are an engineer
That’s exactly why we have safety coefficients.
Safety coefficients are for nerds
That’s a neat trick but also 4% of 75 = (1% of 75) * 4 = 0.75 * 4 = 1.5 * 2 = 3
Ah, joy of commutative algebra.
Wait until you get to noncommutative algebra… shudders. No one who mastered that monster of a subject is sane in any measure.
Yay for quaternions and beyond
I encountered those in game dev a while ago. Honestly, fuck them.
4*75/100This is the way
Is it weird that I just went
start: 75
to actual decimal: .75
*2*2: 1.5 -> 3
Nah we all do weird shit. I did 4x75, then moved from 300. to 3
Meanwhile im the idiot thats like “uh 10% of 75 is 7.5, half it for 5% of 75 is 3.75, 1% of 75 is .75, so its probably 3?”
Lets pray thats one of the options on the multiple choice. Oh the professor wants me to show my math? Well lets hope he’s open to me being an abstract dumbass that is capable of getting the right answer.
I just figured 4% is 1/25 and divided 75/25
Yes, but then I have to do 4 x 75 = 50 + 25 + 50 + 25 + 50 + 25 + 50 + 25 = 50 + 50 + 50 + 50 + 25 + 25 + 25 + 25 = 200 + 100 = 300 in that same order because non-maths brain.
That’s how my brain works as well.
I only learned this a few months ago here on Lemmy and still don’t believe it. It’s magic. You think you’re going to “get it” (trick it) this time, but nope! Still works somehow!
What’s funny is that if someone said (a * b) * c is the same as (c * b) * a, you’d probably say “of course it is”.
Same trick here if you show it as (4* 1/100) * 75 rewritten as (75 * 1/100) * 4.
Yeah, this will be so helpful when I’m trying to figure out 20% of 36.23!
Look, move the decimal one to the left, you’ve now got 10%. Double that and you’ve got 20%. How often are y’all trying to find out percentages of nice even numbers like that?
4 over 100
is
X over 75
And there’s your butterfly.
I also remember a somewhat sinister question: Using a knife, divide 3 apples among 4 people with the less possible cuts. 💀
Sure with easy numbers multiplication is easy. Try anything else.
Why did no one ever teach me this?? Did I miss this day in class? I feel so silly. This is really useful.
Most teachers will write it off as obvious. Taking a percentage of something is just multiplication and if you actually write it down with multiplication, it is, indeed, obvious:
4*75/100=75*4/100And yes, it means you can just multiply 75 by 4 first and then divide by 100.
Yes and no, other day I was trying to figure out 17% of a number like 65, and I’m like “Oh it’s just 65% of 17!” Which really wasn’t helpful.
It works with small numbers on one side tho.
0.75*4
4% is 1/25. 75 is 3*25. so the answer is 3!
3! = 3*2*1 = 6
That’s the same order of magnitude, so still correct!
Just do (7-5)+(5-4)=3
No. Stop it. Just multiply them together. This is useless.
