Question

Subtract 4.66×10⁻⁵-7.34×10⁻⁷
a) 4.66×10⁻⁵
b) 4.66×10⁻⁶
c) 4.66×10⁻⁴
d) 4.66×10⁻⁷

Answer 1

To subtract \( 4.66 \times 10^{-5} \) and \( 7.34 \times 10^{-7} \), we need to express both numbers with the same exponent.

1. Convert \( 4.66 \times 10^{-5} \) to have the same exponent as \( 7.34 \times 10^{-7} \):
\[
4.66 \times 10^{-5} = 4.66 \times 10^{-5} \times \frac{100}{100} = 4.66 \times 10^{-5} = 46.6 \times 10^{-6}
\]

2. Now we can rewrite the expression:
\[
46.6 \times 10^{-6} - 7.34 \times 10^{-7}
\]

To do the subtraction, we also express \( 7.34 \times 10^{-7} \) in terms of \( 10^{-6} \):
\[
7.34 \times 10^{-7} = 0.734 \times 10^{-6}
\]

3. Now we can perform the subtraction:
\[
46.6 \times 10^{-6} - 0.734 \times 10^{-6} = (46.6 - 0.734) \times 10^{-6} = 45.866 \times 10^{-6}
\]

4. Finally, we can denote this in scientific notation, maintaining the same power of ten:
\[
45.866 \times 10^{-6} \approx 4.5866 \times 10^{-5}
\]

Now, looking through the options, we simplify \( 4.5866 \times 10^{-5} \) can be approximately \( 4.66 \times 10^{-5} \) if we round it.

Thus, the answer is:
**a) 4.66×10⁻⁵**.