(i) 0.5 or 0.8

In the above question,

The whole parts of both the numbers are same and the tenth part of 0.8 is greater than tenth part of 0.5

Hence,

0.5 < 0.8

(ii) 2.0 or 0.9

In the above question,

It is clearly seen that whole part of 2.0 is greater than that of 0.9

Therefore,

2.0 > 0.9

(iii) 0.042 or 0.22

In the above question,

Both the numbers have same whole parts but the tenth part of 0.22 is greater than 0.042

Therefore,

0.042 < 0.22

(iv) 3.012 or 2.99

In the above question,

It is clearly seen that whole part of 3.012 is greater than that of 2.99

Therefore,

3.012 > 2.99

(v) 0.055 or 0.15

In the above question,

Both the numbers have same whole parts but the tenth part of 0.15 is greater than 0.055

Therefore,

0.055 < 0.15