Half of it is 5.5 kilograms.
Then it is 10.5-5.5=5 kg (this is 5 kg with half the weight of oil), which means that the original weight of the whole barrel of oil is 10 kg (pure oil does not include barrels).
The original total weight of the barrel and oil is 10.5 kg.
Then 10.5- 10=0.5.
Subtraction formula
1, minuend-subtrahend = difference
2. Difference+Minus = Minus
3, the minuend-difference = reduction
Subtraction correlation characteristic
1, inverse exchange rate: subtraction is inverse exchange. If A and B are any two numbers, then
(A-B) =-(B-A)
2. Anti-association rule: subtraction is anti-association. When trying to redefine subtraction, then
a-b-c=a-(b+c)