Question

write $9.87 \times 10^{-5}$ in standard notation.

Explanation:

Step1: Recall scientific notation rule

For \(a\times10^{-n}\) (where \(1\leq a<10\) and \(n\) is positive integer), we move the decimal point in \(a\) to the left by \(n\) places.

Step2: Apply to \(9.87\times10^{-5}\)

Here, \(a = 9.87\) and \(n = 5\). Moving the decimal point in \(9.87\) to the left by 5 places:
Start with \(9.87\), move left 1 place: \(0.987\) (wait, no, wait: actually, when \(n = 5\), we need to have 5 places. Let's do it properly. \(9.87\times10^{-5}=\frac{9.87}{10^{5}}\). Since \(10^{5}=100000\), divide \(9.87\) by \(100000\).
\(9.87\div100000 = 0.0000987\). Let's check the decimal movement: from \(9.87\), move decimal left 5 times. First move: \(0.987\) (1), second: \(0.0987\) (2), third: \(0.00987\) (3), fourth: \(0.000987\) (4), fifth: \(0.0000987\) (5). Yes, that's correct.

Answer:

\(0.0000987\)