Question

what is 9 in scientific notation?
9x10^1
9x10^1
9x10^0
9x10^2
what is 4.23x10^-4 as a decimal?
0.000423
0.00423
0.0423
0.423

Explanation:

Step1: Recall scientific - notation rule

Scientific notation is of the form $a\times10^{n}$, where $1\leqslant|a|\lt10$ and $n$ is an integer. For the number 9, we can write it as $9\times10^{0}$ since any non - zero number to the power of 0 is 1 ($10^{0}=1$ and $9\times1 = 9$).

Step2: Recall negative - exponent rule for scientific notation

For a number in scientific notation $a\times10^{-n}$ ($n\gt0$), we move the decimal point $n$ places to the left. For $4.23\times10^{-4}$, we move the decimal point 4 places to the left. Starting with 4.23, we get 0.000423.

Answer:

1. C. $9\times10^{0}$
2. A. 0.000423