An expression is a group of two or more terms separated by a math operation, such as addition or subtraction. You can rewrite an expression that has negative exponents as one with positive exponents to simplify the expression. A number or variable with a negative exponent is the same as the reciprocal of the number or variable with a positive exponent. A reciprocal is a number with a numerator and denominator that have switched places. The positive exponent ends up in the denominator if the negative exponent was originally in the numerator, and it ends up in the numerator if it was originally in the denominator.

Find an expression with negative exponents that you want to rewrite with positive exponents. For example, rewrite the expression 3^(-2) + [1/(2^(-2))].

Determine the reciprocal of the base of the first term of the expression. The base is the number with the exponent. For example, the base of 3 is equivalent to 3 over a denominator of 1, or 3/1. The reciprocal of this is 1/3.

Rewrite the original negative exponent as a positive exponent in the denominator because it was originally in the numerator. For example, rewrite the original exponent of -2 as a positive exponent of 2 in the denominator. This leaves 1/(3^2) + [1/(2^(-2))].

Determine the reciprocal of the base of the second term of the expression. For example, the base of the second term is 2, so the reciprocal is 1/2. But because 1/2 is in the denominator, take the reciprocal again to move it to the numerator. This leaves 2 in the numerator without a denominator.

Rewrite the original negative exponent as a positive exponent in the numerator because it was originally in the denominator. For example rewrite the original exponent of -2 as a positive exponent of 2 in the numerator. This leaves 1/(3^2) + 2^2.

Calculate each base raised to its exponent. For example, 3^2 equals 9, and 2^2 equals 4. This results in 1/9 + 4.

Add the fraction and whole number to simplify the expression. For example, add 1/9 to 4, which equals 4 1/9.