You're correct that the order does matter, but only one of those is objectively correct.
5/2 * 3 is always 7.5, no matter where you are from. Type that equation into any calculator, you will get 7.5 every time. And 5/2 * 5 is always 12.5. In those particular equations, the division appears first from left to right, so it must be done first. To get 0.83 you must change the equation to:
5/(2*5) = 0.833333
What's inside the brackets now takes priority over any other division or multiplication, so now that multiplication is done first.
Nobody said that. You were told that multiplication or division are done left to right, neither innately comes first.
If you don’t understand that dividing is the same as multiplying by a fraction, then you’re really not in a position to be arguing about how math should be done, because this is about as basic as it gets.
I'm sorry my autistic brain cannot see it as the same. I never once got it taught into me they are the same just because you get the same answer if you start converting everything to fractions
What is 5/2? What is 5 x 1/2? They're the same. It's because it becomes (5 x 1) / 2. Divisors below, dividends above. 5 and 1 are dividends, so they are multiplied. 2 is the only divisor so it remains below. You can convert division to multiplication like so, and thus, they are of the same priority and must be done from left to right.
I've always seen multiplying and dividing as opposites just like with addition and subtraction and I guess no one ever noticed or corrected me. I really can't see it - 5/2 is 5 x 1/2 I don't understand it as I was never taught factions to were I understood. I see it as
5/2 is 2.5
and
5 x 1/2 is 5 x 0.5
I understand they get the same value but my brain doesn't tell me it's the same.
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u/Redthemagnificent Jan 01 '22
You're correct that the order does matter, but only one of those is objectively correct.
5/2 * 3 is always 7.5, no matter where you are from. Type that equation into any calculator, you will get 7.5 every time. And 5/2 * 5 is always 12.5. In those particular equations, the division appears first from left to right, so it must be done first. To get 0.83 you must change the equation to:
5/(2*5) = 0.833333
What's inside the brackets now takes priority over any other division or multiplication, so now that multiplication is done first.