 Quandaries and Queries Niece has a question that was marked wrong but we are unable to determine how the teacher calculated and arrived at the answer? The problem was as follows: 50 / 5x - y = x=5 y=1 We and niece come up with 1, while the teacher marked the correct answer as -9. Can you help explain how she arrived at this answer? Thanks for any help. Rick Hi Rick, I find questions like this really annoying. It's like reading an English sentence that need a comma to make the meaning clear. Students in school are sometimes taught a a rule called BEDMAS or PEDMAS. It indicates the order of operations in a mathematical expression. B(P) - brackets (parentheses) E - exponentiation D - division M - multiplication A - addition S - subtraction If you follow this rule for your expression, there are no brackets or exponents so first you perform and divisions 50 / 5x - y = (50/5)x - y = 10x - y Next the multiplication 10x - y= (10 5) - y = 50 - y and then the subtraction 50 - y = 50 - 1 = 49 This procedure gives 50 / 5x - y = 49 when x=5 and y=1. Your niece performed the multiplication first. 50 / 5x - y = 50 / (5x) - y = 50 / 25 - y then the division 50 / 25 - y = 2 - y and then the subtraction 2 - y = 2 - 1 = 1 This procedure gives 50 / 5x - y = 1 when x=5 and y=1. I don't see how to get an answer of -9. I suppose you could perform the operations in the order 50 / (5x - y) = 50/(25-1) = 50/24 = 2.083 that is the multiplication, then subtraction and finally division but this doesn't give -9 either. I think there must be a typo somewhere. I don't know any mathematician who would write 50/5x - y. We would all write it as (50/5)x - y or 50/(5x) - y so that the meaning was clear. Harley Rick, The answer of 1 appears correct to me as well. Perhaps there was a typo in the original question and y was supposed to be 11 and not 1, as this would yield an answer of -9. Leeanne Go to Math Central