Negative exponents and scientific notation

[oscar_brown]

holy cow i feel dumb...

i know these are super easy but i just can't figure it out.

1. --- (10^2)^8 divided by (10^-2)^3

2. --- 1.2x10^-6 divided by 4.2x10^-2

if anyone can give me a kick in the brain it would be awsome

1.--- 10^22?
2. -- 2.9x10^5??

 

[hypermorphism]

The first one is correct. The second is not (but only by a sign, typo ?). To check, multiply your quotient by the divisor to see if you get the dividend.

 

[CRGreathouse]

$$(10^2)^8\div(10^{-2})^3=10^{16}\div10^{-6}=10^{16}\cdot10^6=10^{22}$$

$$1.2\cdot10^{-6}\div\left(4.2\cdot10^{-2}\right)= 1.2\cdot10^{-6}\cdot\frac{1}{4.2}\cdot10^2= \frac{1.2}{4.2}\cdot10^{-4}=\frac27\cdot10^{-4}\approx2.9\cdot10^{-5}$$

 

[oscar_brown]

no it wasn't a typo...just dumb
thank you so much, it is amazing how fast you forget stupid things