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06 Numbers and Powers

Power of a Power Rule Calculator: Simplify Exponents

Card No. 06·0236 · Updated · Standard formula, shown below

Simplified power 6
Inner exponent
2
You entered
Outer exponent
3
You entered
You enter
Inner exponent, Outer exponent
You get
Simplified power
Rounding
0 dp

A power of a power rule calculator raises a quantity already written as a power to another exponent, then simplifies the result. Enter the inner exponent and the outer exponent; the calculator returns their product as the new exponent, with the base unchanged.

Formula

The power of a power rule is (xa)b = xab. Here, x is the base, a number or algebraic expression; a is the inner exponent; and b is the outer exponent. The calculator finds ab, the resulting exponent. The base is not entered because it does not affect this exponent calculation. Exponents and the resulting exponent are dimensionless: they have no units.

For example, (x2)3 = x2 × 3 = x6. The rule multiplies the exponents; it does not multiply the base by either exponent.

Worked Example

With the default inner exponent a = 2 and outer exponent b = 3:

  1. Start with (x2)3.
  2. Multiply the exponents: 2 × 3 = 6.
  3. Keep the base unchanged: (x2)3 = x6.

The calculator’s result is 6, the simplified exponent.

How the Rule Works

An exponent tells how many times a base is used as a factor when the exponent is a positive whole number. For instance, x2 means x × x. Raising that power to the third power gives (x × x) × (x × x) × (x × x), which contains six factors of x. That is why the exponents multiply.

The same reasoning applies to numerical bases: (23)2 = 82 = 64, and the rule gives 23 × 2 = 26 = 64. For algebra, (m4)5 = m20.

Negative and fractional exponents also follow the rule under the usual real-number conventions where the expressions are defined. For example, (y−2)3 = y−6, and ((z1/2)2) = z1 when the real-valued expressions involved are defined. A zero exponent gives (xa)0 = x0 = 1 when the expression is defined; the special case 00 is not assigned a universal value in all contexts.

When to Use This Calculator

Use the calculator when an expression has a power raised to another power and you need the resulting exponent. It can check homework, simplify algebra before substituting values, or help keep track of exponent arithmetic in a longer expression. Enter exponents as numbers, including negative values or fractions if needed; for a fraction, use its numerical value, such as 0.5 for one-half.

  • For (q7)4, enter 7 and 4. The result is 28, so the expression is q28.
  • For (r−3)2, enter −3 and 2. The result is −6, so the expression is r−6.
  • For ((s2)3)4, apply the rule twice: 2 × 3 × 4 = 24. A calculator used successively gives the final exponent 24.

The displayed result is the exponent only. To write the complete simplified expression, place that result on the original base. For example, if the base is (u + 1), then ((u + 1)2)3 becomes (u + 1)6, not u6 + 1.

Distinguishing Similar Exponent Rules

A frequent mistake is applying the power-of-a-power rule where a different exponent rule is needed. The structure of the expression determines what to do:

  • Power of a power: (xa)b = xab. Multiply the exponents.
  • Product raised to a power: (xy)b = xbyb. Apply the exponent to each factor.
  • Product of powers with the same base: xaxb = xa+b. Add the exponents.
  • Quotient of powers with the same base: xa/xb = xa−b, for x ≠ 0. Subtract the exponents.

These rules are not interchangeable. For example, x2x3 is x5, not x6, because it is a product of powers rather than a power raised to a power.

Common Problems and Limits

Parentheses matter. In (x2)3, the outer exponent applies to the entire inner power, so the exponents multiply. In x23 written without clear grouping, the intended structure may be ambiguous; use parentheses to show exactly what is raised.

Do not confuse multiplying exponents with evaluating the base. The calculator does not return the numerical value of xab, because it has no base input. If you need a numerical power, first find the simplified exponent and then evaluate the expression using the specific base. For instance, simplifying (23)2 gives 26; evaluating it gives 64.

Fractional exponents can introduce domain restrictions over the real numbers. For example, a square root of a negative number is not real, while some odd roots of negative numbers are real. The multiplication rule remains an exponent identity, but transformations involving fractional powers should be checked against the domain and the meaning of the powers in the problem. In complex-number settings, branch conventions can also matter. The calculator simplifies the exponents; it does not verify that a particular base and exponent combination is valid in every number system.

Finally, the calculator uses ordinary numerical multiplication. If exponents are very large or are entered as approximations, the displayed result may be rounded by the interface. Keep exact fractions or symbolic expressions by hand when exact form matters.

Frequently Asked Questions

What is the power of a power rule?
It is (xa)b = xab: keep the base and multiply the inner and outer exponents.

Do you add or multiply exponents in this rule?
Multiply them. Addition is used when multiplying powers that have the same base, such as xaxb.

Does the rule work with negative exponents?
Yes, provided the original expression is defined. For example, (x−2)3 simplifies to x−6; a negative exponent means a reciprocal when the base is nonzero.

What happens when the outer exponent is zero?
The new exponent is zero, so the expression becomes x0 = 1 for a nonzero base. Expressions involving zero to the zero power require special care because that case has no single universal convention.

Does the base change when you apply the rule?
No. The base stays exactly as it was, including any parentheses around a compound base. Only the exponents are multiplied.

Can I use this calculator for a product like x²x³?
That is a different rule. For powers with the same base multiplied together, add the exponents: x2x3 = x5.

Related

Formula used
in a | Inner exponent | - | 2 | 0
in b | Outer exponent | - | 3 | 0
out result | Simplified power | - | a * b | 0

Each line is one input (in, sel, list) or one result (out: label, unit, formula, decimals). How the calculators work

Method: the standard formula for this calculation, rounded as each result states. See how the calculators work or report an error.

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