Question

Need help determining a particular equation!

Answer 1

\[\frac{ 1.0 * 10^{-15}}{ 4.2 * 10^{-7} }\]

Must be answered using two significant figures. I'm trying to solve this on my calculator and it's not working.

Answer 2

\[\frac{ 1.0 \times 10^{-15}}{ 4.2 \times 10^{-7} }\]
Both 1.0 and 4.2 have two sig figs, so the quotient must also be written with two sig figs. Keep that in mind.

You can reduce the division of the powers of ten (the \(10^{\cdots}\) part) to subtraction:
\[\frac{ 1.0 \times 10^{-15}}{ 4.2 \times 10^{-7} }={\large\frac{1.0}{4.2}\times10^{-15-(-7)}}={\large\frac{1.0}{4.2}\times10^{-8}}\]