Dividing a number by 10 is probably the easiest thing to do, you just need to follow these rule :
1. If the number that has zero divided by 10, you just need to take out 1 zero
Example : 200 : 10 = 20
2. If the number that doesn't has zero divided by 10, you just need to put a comma in front of the last number
For example : 1998 : 1 = 199.8
hope this helps