8<х<_13

8 < x < 13 means x is strictly between 8 and 13.

• Real numbers: x ∈ (8, 13)
• If x is an integer: x ∈ {9, 10, 11, 12}
• On a number line: open interval with endpoints not included

Examples: x = 9 works; x = 8 or x = 13 do not. If you want, I can help with related inequalities.