Compare Powers: (3/10)^7 vs 0.3^8 - Which Value is Larger?

Exponent Comparison with Decimal Fractions

Which is larger?

(310)7 ——(0.3)8 (\frac{3}{10})^7\text{ }_{——}(0.3)^8

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Step-by-step video solution

Watch the teacher solve the problem with clear explanations
00:00 Determine which is greater?
00:08 Convert decimal number to fraction
00:16 The fraction with the larger exponent is greater
00:22 And this is the solution to the question

Step-by-step written solution

Follow each step carefully to understand the complete solution
1

Understand the problem

Which is larger?

(310)7 ——(0.3)8 (\frac{3}{10})^7\text{ }_{——}(0.3)^8

2

Step-by-step solution

To determine which of the two expressions is larger, we need to evaluate them using a comparability method:

  • Step 1: Observe that these are powers of a common base. We first convert (0.3)8 (0.3)^8 to a fraction form. The number 0.3 0.3 is equivalent to 310 \frac{3}{10} .
  • Step 2: Thus, (0.3)8 (0.3)^8 becomes (310)8 \left(\frac{3}{10}\right)^8 .
  • Step 3: We then compare (310)7 \left(\frac{3}{10}\right)^7 and (310)8 \left(\frac{3}{10}\right)^8 . Since both have the same base, 310 \frac{3}{10} , we compare the exponents directly: 7 7 and 8 8 .
  • Step 4: Clearly, any number to the power of 7 will be larger than the same number to the power of 8, since raising a positive fraction to a higher power results in a smaller number.

This analysis shows that (310)7 \left(\frac{3}{10}\right)^7 is larger than (0.3)8 (0.3)^8 . Therefore, using the symbol for comparison:

The correct comparison is (310)7>(0.3)8 (\frac{3}{10})^7 > (0.3)^8 .

Accordingly, the solution to this problem as stated is incorrect in the given answer. The correct comparison should indeed be:

(310)7>(0.3)8 (\frac{3}{10})^7 > (0.3)^8

3

Final Answer

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Key Points to Remember

Essential concepts to master this topic
  • Base Rule: When comparing powers with same base, compare exponents
  • Technique: Convert 0.3 to 310 \frac{3}{10} to reveal common base
  • Check: Since 310<1 \frac{3}{10} < 1 , higher exponents make smaller values ✓

Common Mistakes

Avoid these frequent errors
  • Thinking higher exponents always mean larger values
    Don't assume that 8 > 7 means (0.3)8>(310)7 (0.3)^8 > (\frac{3}{10})^7 = wrong comparison! This rule only works for bases greater than 1. Always remember that for fractions less than 1, higher exponents create smaller values.

Practice Quiz

Test your knowledge with interactive questions

Write the following fraction as a decimal:

\( \frac{5}{100}= \)

FAQ

Everything you need to know about this question

Why does a higher exponent make a smaller number when the base is a fraction?

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When you multiply a fraction by itself, you get a smaller fraction! For example: 310×310=9100 \frac{3}{10} \times \frac{3}{10} = \frac{9}{100} which is smaller than 310 \frac{3}{10} . Each multiplication makes it even smaller.

How do I convert 0.3 to a fraction quickly?

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Remember that 0.3 means 3 tenths, so it equals 310 \frac{3}{10} . Any decimal with one digit after the decimal point becomes a fraction with 10 in the denominator.

What if the bases were different fractions?

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You'd need to calculate both values or convert them to have a common base. The trick of comparing exponents only works when the bases are exactly the same.

How can I remember when higher exponents make smaller values?

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Think: "Fractions shrink when multiplied!" If the base is between 0 and 1, raising it to higher powers makes it smaller. If the base is greater than 1, higher powers make it bigger.

Can I use a calculator to check my answer?

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Absolutely! Calculate (310)70.0000218 (\frac{3}{10})^7 \approx 0.0000218 and (0.3)80.0000066 (0.3)^8 \approx 0.0000066 . You'll see that (310)7 (\frac{3}{10})^7 is indeed larger.

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