An important step in problem solving before mathematically solving an equation is?

Question

A) checking units, B) checking significant figures, C) consulting with a friend, or D) checking to see if the result is reasonable.

Answer 1

I would say D. Usually, if the answer in a word problem is wrong, you can tell if you look back at the question. If you're asked about how much water would fill up a pool and you come up with three gallons, something is seriously wrong.

Edited to add: Apparently I read the question wrong? It still seems to me that checking to make sure that the answer you're getting would make sense. If you start a question trying to solve for the wrong thing, what's the point in attempting the problem in the first place?

Answer 2

Mathematically, units don't make any difference. Equations don't include units. You're dealing only with numbers or variables or both. If it's a word problem, then I'd go with this option. But you said "equation." Like 3a+5 = 8, or A=πr² or A=π(6²)

Mathematically the accuracy (significant figures) doesn't make any difference before you go to work to do the arithmetic. You just do the arithmetic. If accuracy is of any importance, it is so only after the solution is reached.

Sorry... "C" is a throw-away answer. But it's about as good as any of the others. It just requires less thought to eliminate.

You can't check the reasonableness of the solution without solving the equation. Kind of hard to do BEFORE you do so.

To me, unless I'm misinterpreting something, none of the options seem to make any sense.

Answer 3

I would say A, but for a slightly different reason than the first answer--

You want to make sure that the units on each side of the equal sign are the same. If you come up with energy on one side, and mass on the other, you know that there's something wrong.

B would be done after you get the answer, and D would also be done after the answer. However, before you work it out, you should have some idea of what is a reasonable answer.

Answer 4

The key word in the question is BEFORE.

A -Always check your units. Some problems may present 2 figures in different units and you might need to convert one in order to get the correct answer. If one thing is, say, in metres and the other is in feet, you'll need to do a conversion one way or another to get the right answer

Why are the others wrong?:

B - sig figs only matter if the question is asking for an answer in certain sig figs after you get the answer.

C - Your friend might be an idiot

D - This happens AFTER you solve mathematically.