To find the difference between,
[tex]400[/tex]
and
[tex]273[/tex]
means what number should we add to 273 to obtain 400.
To find that number, we subtract 273 from 400.
To do that we need to set up the numbers as below to make the calculation easy for us.
[tex] \: \: \: \: \: \: \: \: 10 \\ \: \: \: \: 39 \\ \: \: \: \: 400 \\ \frac{ - 273}{ \: \: \: \: 127} [/tex]
We do the subtraction from right to left.
The first digits are 0 and 3. Since 0 is less than 3, we 'borrow' from the next digit.
But sad for us, the next digit to the right is also zero. So we borrow from the from the first non-zero digit which is 4.
Borrowing 1 from 4 makes the hundred digit reduce to 3. Since we are operating in base 10, the 1 we borrow has a value of 10. Adding that 10 to the zero at the immediate right of 4 makes it 10. Now we can borrow one from this "10". That makes it become 9. That is why you are seeing '39' at the top of the '40'. Now our right mist zero has a value of 10(written at the topmost right).
We subtract 3 from 10 now to get 7.
Then 7 from 9 to get 2.
and 2 from 3 to get 1.
Hence
The difference between,
400 and 273 is 127.
