How do i make observations and calculate data involving metric units?

Define qualitative and quantitative observations.
Distinguish between qualitative and quantitative observations.
Use Quantitative observations in measurements.
State the different measurement systems used in chemistry.
State the different prefixes used in the metric system.
Do unit conversions.
Use scientific notation and significant figures.
Use basic calculations and dimensional analysis.
Use mathematical equations in chemistry.
(i hope this helps??)

The formula is (nh4)2co3