Theory:

"The digits are multiplied without using the decimals. Then the decimal point separates as many decimal digits as there are in the multipliers together."
2.5×1.6¯15025¯4.00
First, multiply by articles as integers:
(2516=400)
 
Then point separated the last \(2\) digits (\(00\)).
2.5×1.6=4.00=4
2.75×0.16¯16502750.4400¯
First, multiply by articles as integers:
(27516=4400) 
 
Then point separated the last \(4\) digits (\(4400\)).
2.75×0.16=0.4400=0.44
 
0.01111×55.5=0.616605
 
First, multiply the digits as integers. 
 
(1111×555=616605)
 
Then the point separated the last \(6\) digits (\(616605\)). 
  
0.01111×55.5¯5555555555550.616605¯