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A comment on Learning algebra in my 60s. Parent comment

Re:Learning algebra in my 60s by gamerDude on Monday August 08, 2022 @10:56AM (#32386195)
I work with K12 schools in the U.S. and one of our really sad stories is how a calculus students failed to solve a "A t-shirt that costs $15 is 20% off today. How much does it cost after the 20% discount (don't include tax)?" <-- not the exact wording, but you get it.

They responded, "I don't remember the formula for a sale". Only knowing formula's is terrible, it makes knowledge super fragile. So, I for one support your idea of emphasizing understanding over formula memorization!

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Re:Learning algebra in my 60s by WalterBright on Monday August 08, 2022 @11:43AM (#32386914)
I feel that way about the % key on calculators that also have a / key. If you need a % key, you have no business using one :-/
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Re:Learning algebra in my 60s by ravi-delia on Monday August 08, 2022 @01:37PM (#32388553)
Eh, the closer you can get to entering a formula without the mental effort of backtracking and lookahead the better. It's like fraction buttons; obviously you can just think ahead and use parenthesis with division, but a smart fraction button will save a lot of time
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Re:Learning algebra in my 60s by WalterBright on Monday August 08, 2022 @01:49PM (#32388705)
What's 20% of $59.22?

    .2 * 59.22
What price is $2.99 milk with 9.2% inflation?

    2.99 * 1.092
What did $5.00 gas cost last year?

    5.00 / 1.092
I'm not seeing backtracking and lookahead.
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Re:Learning algebra in my 60s by ravi-delia on Monday August 08, 2022 @04:21PM (#32390532)
You'll note that English is written left to right. In the string "20%" there is a "2", a "0", and a "%" arranged from left to right. To type that string into a calculator, one could press "2", "0", and "%" in that order, or "0", ".", "2", in that order. To know to lead with "0." rather than "20", you have to look ahead.

For the others you'd have to do the mental work to append a 1 regardless, might as well stick with decimals

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