World War 2 officially started on September 1, 1939 when Germany invaded Poland and most other nations which were part of the British Empire and Commonwealth declared war on Germany.
Answer:
#1 is 34
#2 can't answer properly without knowing where the other () go
#3 can't tell what the fractions are so I can't help
Answer:
Milli is 1*10^-3
Explanation:
For every 1000 millimeters we have 1m.
1000mm=1m