how to apply automatic difference

calculate how many kilometers each vehicle traveled each month

For example, why not assign the kilometers made between January 19 (117) and February 2 (240) to a month or months?
Or divide the kilometers evenly over the (intermediate) time range?
In this case: January 12/14*(240-117) and February 2/14*(240-117)??

Hello Kid806022 and Welcome to Excel Forum.
Perhaps the following will work:

Formula:

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I don't understand why cell E4 should report zero and cell E10 should report 208. It would seem that either both should be zero or E4 should be 29.
Let us know if you have any questions.

Try pasting the following into cell E2 and copying down:

Formula:

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In the sample the #NUM! error occurs when the vehicle changes from the row above.
The following removes the #NUM! errors in those cases:

Formula:

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Let us know if you have any questions.