# How to make 18 from 1, 3, 4, 8

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.

• Welcome to Puzzling.SE! I have a few questions - 1. Can the order of the numbers be changed? 2. Did you omit division on purpose or by accident? 3. Are there any other allowed operators (concatenation, exponents, roots, etc. Mar 18 '19 at 22:18
• @Brandon_J, Order of numbers can be changed. Division and other operations intentionally omitted. Mar 18 '19 at 23:18
• @ferret I've updated the question with the original worksheet. Mar 18 '19 at 23:18
• I suspect that the teacher either meant 16 or 17, as both are possible. Mar 19 '19 at 2:02
• I just added an answer. It was, in fact, a typo. Mar 22 '19 at 14:26

$$18 * (4-3) = 18$$