TI-80, TI-81, TI-82, TI-85這幾台都是早期型號
TI-83, TI-84, TI-86, TI-89, TI-92, Nspire這幾台是比較新的
與其說是功能取向不同...不如說是把bug修掉了

特別弄出來的功能，你要稱之為BUG。= ="

因為TI也沒特別說明，後期大部分的機型為什麼會取消掉這個功能。

我也不會去隨便臆測他們的動機是什麼。

只能就他們公布的說明來看，TI-80, TI-81, TI-82, TI-85機型是刻意設計出來的。

這個DR.Peterson的結論不就跟之前DR.IAN一樣嗎!?都是建議將A*B/X*Y當成是(A*B/X)*Y,而不是 (A*B)/(X*Y)...
原文如下:
I prefer the standard way (your first answer) when talking to students,
unless their own text gives the "implicit multiplication first" rule...
請注意(your first answer)是指發問者的第一個算法,也就是(A*B/X)*Y而不是(A*B)/(X*Y), 原發問者問題如下:
The problem was presented like this:

a = 1.56
b = 1.2
x = 7.2
y = 0.2

ax/by = ?

Here are two ways that I solved it:

1) I first rewrote the problem as [1.56(7.2)/ 1.2](0.2). Second, a was
multiplied by x. The product was 11.232. Then, since no parentheses
were present, I followed the order of operations and divided 11.232 by
b, which was 1.2. The quotient was 9.36. Then I multiplied 9.36 by y,
which was 0.2. The final answer was 1.872.

2) The other way, the first thing I did was multiply a by x. The
product, which was 11.232, was set aside for the time being. Then b
was multiplied by y, which gave the product of 0.24. The problem was
now solved by dividing 11.232 (or ax) by 0.24 (or by) to reach a final
answer of 46.8.

Can you please tell us which answer is correct and why?

變數有點混到,所以重寫一次!
這個DR.Peterson的結論不就跟之前DR.IAN一樣的看法嗎!?都是建議將ax/by當成是(ax/b)*y,而不是 ax/(by)...
原文如下:
I prefer the standard way (your first answer) when talking to students,
unless their own text gives the "implicit multiplication first" rule...
請注意(your first answer)我認為是指發問者的第一個算法,也就是(ax/b)*y而不是ax/(by), 雖然Dr.文中解適過程有自己把兩個順序顛倒,但我是認為這個your first answer應該是指發問者原始的first answer.
原發問者問題如下:
The problem was presented like this:

a = 1.56
b = 1.2
x = 7.2
y = 0.2

ax/by = ?

Here are two ways that I solved it:

1) I first rewrote the problem as [1.56(7.2)/ 1.2](0.2). Second, a was
multiplied by x. The product was 11.232. Then, since no parentheses
were present, I followed the order of operations and divided 11.232 by
b, which was 1.2. The quotient was 9.36. Then I multiplied 9.36 by y,
which was 0.2. The final answer was 1.872.

2) The other way, the first thing I did was multiply a by x. The
product, which was 11.232, was set aside for the time being. Then b
was multiplied by y, which gave the product of 0.24. The problem was
now solved by dividing 11.232 (or ax) by 0.24 (or by) to reach a final
answer of 46.8.

Can you please tell us which answer is correct and why?

A×B="AB"
同理可證，
故
A×B÷A×B
=AB÷AB
所以AB÷AB≠1
把"答案"跟運算式子搞混了，誤認為式子中運算符號可以省略，
，拿"答案"來改寫式子，濫用省略*符號。

A×B="AB"
3AB-2AB="AB"
AB(3-2)="AB"
-----------------------

式子中"AB"÷"AB"在寫求解計算過程時應寫成"(A×B)÷(A×B)"，。
式子中的AB不是A×B省略，是答案.
因誤認為式子中運算符號可以省略，進而看成A×B的縮寫。

---------------------------
(A×B)÷(A×B)
="AB"÷"AB"
=1
A×B÷A×B
="AB"÷A×B