Metric System
What you need to know about it...
Base Units (MKS system)
metre (m) - https://en.wikipedia.org/wiki/2019_redefinition_of_SI_base_units#Metre
kilogram (kg) - redefined in 2019 - https://en.wikipedia.org/wiki/2019_redefinition_of_SI_base_units
second (s) - https://en.wikipedia.org/wiki/2019_redefinition_of_SI_base_units#Second
more at: http://www.si-units-explained.info/
Prefixes you should know and use:
tera (T=1012) - you have a computer harddrive this big!
giga (G=109)
mega (M=106)
kilo (k=103)
hecto (h=102) as in hectare (100 m x 100 m)
deca (da=101) like decade!
-- (100) - no prefix!!!
deci (d=10-1) like decimate!
centi (c=10-2) - but only for distance!
milli (m=10-3)
micro (µ=10-6)
nano (n=10-9)
Usage:
with scientific notation, use only the base unit and unit digit with decimals
with prefixes, only hundreds, tens and unit digits with decimals are allowed
a space after the number, before the unit please!
with errors (uncertainties):
9.8 ± 0.5 cm (note: 1 digit on the absolute error in the same position as the last digit of the value)
9.8 cm ± 5.1% (note: 2 digits on the percentage error)
with a calculator - there is a Scientific Notation button: [EE], [EXP] or [x10x]. Use It !
NEVER use:
[10x] ie "2nd" "log",
[x][10][yx] ie exponent button [yx] or [^] or [x¤], or
any other button which requires you to use brackets with scientific notation. For example 2x103 squared should give you 4,000,000 without using brackets, not two billion
you can change the display of the calculator to scientific notation... learn how from your manual. (lost it? search for your calculator model and the word "manual")
Related:
Rounding and Significant Figures
see science skills expectations chart.