This question was on my sister's 5th-grade homework, practicing order of operations. It was to make 18, using the numbers 1, 3, 4, 8 and the operations +, -, and *. The instructions imply using each operation only once. Additionally, grouping with parenthesis is allowed.
Neither my sister, my father, or I were able to find a solution. I even tried writing a python script to attempt all possible solutions to the problem, to no avail.
Can you do what we can't? Or is the problem flawed?
Edit: Here is a picture of the original worksheet. The problem in question is #11. I assume that operations are only allowed once, because some of the other problems have an operation repeated, and because it refers to rearranging operations and numbers on a mat.