You get the incorrect.56 answer if you start at the beginning of the problem and work straight through, from left to right. 7 plus 7 is 14, divided by 7 is 2, plus seven is 9, times 7 is 63, minus 7 is 56. You did all the work and made it to the end, but it was wrong.
Turns out that the way you do something is just as important - and often even more important - that whether you get to the end or not.
In this case, you have to follow the "order of operations." The acronym is PEMDAS (even my 10-year-old can quote "Please Excuse My Dear Aunt Sally"). I wonder what dear Aunt Sally did to earn such elementary school notoriety... You have to approach a math problem in the correct order: Parenthesis, Exponents , Multiplication, Division, Addition, Subtraction. Actually, the multiply/divide can be done together, as can the add/subtract.
When you follow the correct order, the problem looks different. 7+ 7/7 + 7*7 -7. Work through the multiply and divide parts of the problem first, the go for the add and subtract. Same original numbers, but now you get a different answer. The correct one.
I think I too often try to slog through a problem from left to right without looking at the whole thing and figuring out what the order of operations is. Whatever is on front of me, that is the part I need to tackle. But if I step back and figure out what the most important things are, and do those first, then I arrive at a totally different solution.
And it's the right one.
The correct answer is c) 50. Thanks to my smarty-pants kids who helped me figure it all out completely - and 4 of the 5 got the right answer, too!