john has $3.05 he subtracts $1.18 and is left over with $1.87
first john subtracts the 8 from the five but he cant do that so he takes from the 3 and makes it a 2 he then moves over that ten that he had taken away from the 3 and places it at the 0. Now john needs to move over the 10 on the 0 to the 5 so he can subtract the 8 from the 5. John moves one ten from the nine that had replaced the 0 and gave it to the 5. that 5 is now a 15 because you've added ten to it. John now subtracts the 8 from the 15 to get 7 . next john subracts the 9 from the 1 in the tens place to get 8. Now john subracts the 1 from the 2 in the hundereds place to get a total sum of $1.87.
or
3.05
-1.18
---------
1.87