It is not good enough to know (and convey) the precision of
*measurements*. We will almost always have to *do
something* with those numbers, we therefore need to consider
how is our precision affected by arithmatic manipulation.

- multiply and divide -> get lowest number of sig. figs.
- add or subtract -> the last sig. fig. in each number is compared, keep only the (last) sig. fig. which is furthest left (the "largest")

OUTCOME:

Determine the number of significant digits both in a given value as well as in the result of arithmetic

TEST YOURSELF!

How many significant digits are there in
2.04x10^{-3}?

TEST YOURSELF!

Your Car weighs 2100 lb_{f}

You put an 8 lb_{f} bag in the trunk

What is the car's weight now?
[cheat]

TEST YOURSELF!

You measure a samples mass to be 3kg

Calculate the samples weight (multiply by gravity: 9.81
m/s^{2})

What is your answer?
[cheat]