• Capt. Wolf@lemmy.world
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    1 year ago

    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

    or

    (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
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      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.