To find the difference between the boiling points of oxygen and hydrogen, we'll subtract the boiling point of hydrogen from the boiling point of oxygen.
Boiling point of oxygen: -182.9 °C
Boiling point of hydrogen: -252.87 °C
Now, calculate the difference:
\[ \text{Difference} = \text{Boiling point of oxygen} - \text{Boiling point of hydrogen} \]
\[ \text{Difference} = -182.9 - (-252.87) \]
This simplifies to:
\[ \text{Difference} = -182.9 + 252.87 \]
Now, perform the addition:
\[ \text{Difference} = 252.87 - 182.9 = 69.97 \]
Thus, the difference between the boiling points of oxygen and hydrogen is:
\[ \boxed{69.97} \]