please tell me what 16/7+86.8 is

Set up your problem. (Always put the bigger number on top.) So what your problem should look like is 86.8 on top and the fraction on the bottom.
Break down the fraction: (So your fraction would have 1. The decimal. And 2. It's way easier to work with when you have two whole numbers/decimals.)

So your broken down fraction should have the numbers in this specific order: 2.28571429

Add the two number together: (Add 2.28571429 and 86.8)

You would start at the end of your problem

9 + 0 = 9

2 + 0 = 2

4 + 0 = 4

1 + 0 = 1

7 + 0 = 7

5 + 0 = 5

8 + 0 = 8

2 + 8 = 10

2 + 86 = 88 + 1 (From the 10) = 89

So, to conclude, 16/7 + 86.8 = 89.08571429

Then, simplified it is: 89.08 or 89.0/89

If you need to simplify to only one digit after the decimal, the answer would be 89

If you are wondering why then the reason why you wouldn't add the .0 is because you never add the .0 at the end. If your answer is 89.08 then you cannot take away that 0 because you only take away the 0 if its at the end of your answer.

(Examples.)

X for Don't take away 0

[tex]\sqrt[/tex] for Take away 0

89.08 X

37.30 [tex]\sqrt[/tex]

12.6802 X

15.670 [tex]\sqrt[/tex]

16.05 X

15.50 [tex]\sqrt[/tex]

6.903 X

And so on.