Question

put the numbers in order from least to greatest.
least
↓
greatest
= 2.1 x 10^(-5)
= 1.4 x 10^(-8)
= 6.3 x 10^(-5)
= 3 x 10^(2)

Explanation:

Step1: Compare exponents

When comparing numbers in scientific - notation $a\times10^{n}$, first compare the exponents $n$. Smaller exponents mean smaller numbers (when $a>0$). The exponents are $- 8$, $-5$, $-5$, and $2$.

Step2: Compare numbers with same exponent

For the numbers with the same exponent ($2.1\times10^{-5}$ and $6.3\times10^{-5}$), compare the values of $a$. Since $2.1<6.3$, $2.1\times10^{-5}<6.3\times10^{-5}$.

Step3: Order the numbers

Based on the above - mentioned comparisons, the order from least to greatest is: $1.4\times10^{-8}<2.1\times10^{-5}<6.3\times10^{-5}<3\times10^{2}$.

Answer:

$1.4\times10^{-8},2.1\times10^{-5},6.3\times10^{-5},3\times10^{2}$