Created SC1076 (markdown)

SC1076.md

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+## Trying to do math? Use e.g. `[ $((i/2+7)) -ge 18 ]`.
+
+### Problematic code:
+
+```sh
+[ i / 2 + 7 -ge 18 ]
+```
+
+### Correct code:
+
+```sh
+[ $((i / 2 + 7)) -ge 18 ]
+```
+### Rationale:
+
+ShellCheck found a loose `+*/%` in a test statement. This usually happens when trying to do arithmetic in a condition, but without using the arithmetic expansion construct `$((expression))`.
+
+In C, `if (a+b == c)` is perfectly fine, but in sh this must be written to first expand the arithmetic operation like `if [ $((a+b)) = c ]`.
+
+### Exceptions:
+
+None.
+
+### Related resources:
+
+* Help by adding links to BashFAQ, StackOverflow, man pages, POSIX, etc!