The missing word is "equal".
In fact, The relationship between temperature in Celsius and temperature in Kelvin is
[tex]T(^{\circ}C) = T(K)-273.15[/tex]
So, the absolute value of the two temperatures are different. However, there is a direct proportionality between the temperature in Celsius and the temperature in Kelvin, this means that temperature differences are equal in both units.
Let's see this with an example: let's call [tex]T_1 (C)[/tex] and [tex]T_2 (C)[/tex] two different temperatures in Celsius, and let's rewrite them in Kelvin using the previous relationship:
[tex]T_2 (C)-T_1 (C) = T_2(K)-273.15-(T_1(K)-273.15) = T_2(K)-T_1(K)[/tex]
as we can see, both the 273.15 cancel out and so the temperature difference in Celsius is equal to the temperature difference in Kelvin.
