ok so 10 pennis is 1 dime which is 10 cents ok lets go to the next number 20 pennis will be 2 dimes because its the same cents then 30 pennis will be 3 and 40 will be 4 so just divide 10 into the number of pennis or in this case you have a easy out you can just use the numbers infront of the zero since you are talking about dimes.
It would even be the same if you had 2,300 pennis you would have 230 dimes