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Sereaph t1_iyc1wc1 wrote

Reply to comment by Way2Foxy in ELI5 why we first multiply, then add by TheManNamedPeterPan

you're trying to be clever using those decimals, but the concept is still the same.

First let's convert those decimals into symbology that's easier to work with (fractions):

0.75 = 3/4

0.44 = 11/25

0.75 x 0.44 = 3/4 x 11/25

So therefore using ADDITION to evaluate the multiplication of the fractions,

11+11+11 = 33 for the numerator

25+25+25+25 = 100 for the denominator

The fraction 33/100 simplifies to 0.33 in decimal form.

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Way2Foxy t1_iyc2s6k wrote

I wasn't trying to be clever, I was just choosing random numbers.

You're right, though, and you definitely can use long multiplication to multiply any two rationals using only addition (though not sure if/how you can reduce to the lowest terms).

I got lost/distracted and started arguing something I didn't mean to initially. My initial argument that I still hold is that you can't define multiplication as simply repeated addition, and to further clarify I mean strictly that if you multiply a and b you add a to itself b-1 times.

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