Most countries use the Metric System, which uses the measuring units such as meters and grams and adds prefixes like kilo, milli and centi to count orders of magnitude.
299,792,458 m/s
3 * 108 m/s (scientific)
299.79 * 106 m/s (engineering)
In the USA and UK, the older Imperial system is used, where things are measured in feet, inches and pounds.
1,079,252,848,800 m/hr
983,571,056 ft/sec
31,556,736 secs
1.0 yrs
31.56 * 106 sec(s)
525.95 * 103 min(s)
8.77 * 103 hr(s)
365.24 day(s)
52.18 wk(s)
1 year(s)
9,460,471,451,897,088 meter
63.24 * 103 astronomical unit
9.46 petametre
999.97 * 10-3 lightyear
306.59 * 10-3 parsec
