I totally remember being taught this. It's just way easier to break down percentages in terms of the nearest 1% or 10% times the number in the percent times the number you're taking the percentage of. You don't have to do the math for the 1 or 10 percentage as long as you remember that a 10% means move the decimal left once and 1% means move the decimal left twice. The rest is just basic multiplication.

40% of 59 = 10% of 59 times 4.

So...

4x59=236

(4x50=200) + (4x9=36)= 236

10% means move the decimal left once,

Therefore 40% of 59 is 23.6

With that you can easily do more complex percentages mentally like...

62% of 35 = 10% of 35 times 6 plus 1% of 35 times 2.

35x6=180+30=210 at 10% so 21

plus

35x2=60+10=70 at 1% so 0.7

Therefore 62% of 35 = 21.7

[–] _cnt0@sh.itjust.works 1 points 1 year ago

While I get your sentiment, I'm always baffled how people fail to just memorize some basic formulas/equations and then just to plug and play:

1÷kⁿ = k⁻ⁿ

% = 1÷100 = 10⁻²

k×10ⁿ equals k with its floating point shifted by n to the right for positive n, or to the left for negative n

That's really all one needs to know for the "problem" at hand. For your concrete example of "40% of 59" that would just be

59×40×10⁻²

Just solve that whatever way is easiest. I don't get why people get panic-stricken when they see the % sign.