To say there is no right answer when it comes to math, to some, is akin to heresy. More than that, some might say it’s illogical and completely erroneous.
Math is math; it doesn’t change. But the truth is, it does, and has changed.

And arriving at different answers all has to do with the order of operations. As an example, if you're taught, all of your life, that the standard color of the sky is called "red", then you perhaps will grow up thinking all colors of blue are actually called different shades of red.Or, if you are told a blue color is teal, but someone else takes it turquoise, you might find yourself in a debate of suitable colour names. While it's easy to argue that phoning blue "red" is incorrect, it is not really easy to state that blue-green is not both teal and turquoise, depending on who you ask. In the matter of you and the other individual, you're both taught different things about the same colour.

And Sometimes, a similar issue happens where math is concerned. Except, With math, it will get a bit more rigid than color titles, as it involves Using a set of instructions in order to arrive at the right answer. Most men and women know these instructions as the order of operations. And Different individuals are taught different things about the correct order.
For example, how would you solve the following equation?



If you end up with an answer of either 1 or 9, you’re not alone.

The vast majority of people ended up with either one of those answer. Some reportedly think it is 0, 3, or even 6, but none of those three answers are at all correct.

However, the reason why 9 and 1 are given as the main answers for this problem all boils down to how people were taught to do math.
For an explanation of why the answers to this math problem vary, watch this video:



Source: https://aderonkebamidele.com/math-problem-internet-stumped-know-right-answer/