Based on the definition of a coefficient, the coefficient in the expression n+10 is 1.
In Mathematics, an algebraic expression is a type of mathematical equation which is typically used for showing the relationship existing between two or more variables, numerical quantities (constants), accompanied with the use of different mathematical operations.
A coefficient is a constant quantity, numerical data, or numerical value that is typically placed before the variable in an algebraic expression.
In this context, we can logically deduce that the variable term in the expression n+10 is n, which has a coefficient of 1, even though the one (1) is not written.