In order to write 8.9 In Simplest Form; first one has to remove the decimal point from decimal number like this

8.9 = 89/10

Now divide 89 by 10 you will get

8

10 | 89

80

9

so the answer is 8 9/10

8.9 = 89/10

Now divide 89 by 10 you will get

8

10 | 89

80

9

so the answer is 8 9/10