How do you write fraction 9/10 as a decimal
and how to convert fractions into decimals

9/10 you will have to multiply 10 by 10cto get 100 so you do the same to 9. So its 90/100 so in decimal form its .90 
To convert fractions into decimals you multiply the denominator until you get to 100 or 200 and ect. Or you can divide the numerator by the denominator for example 9 divided by 10 is .9 (:

1) we write 9/10 as 0.9 in decimal form.

2) To convert fractions into decimals, all you have to do is divide the numerator by the denominator by the long-division process. If you practise regularly, you will be able to do it without the long division process.