difference between two time values

[learning_grexcel]

Hi,

I have a column with values A1 = 1030; a2=1031; a3=1034; a4=1152; a5=1153; etc.

These values represent time "1030" means 10.30 am; 1152 means 11.52 am, respectively.

I want to find the difference between a1 and a2; a2 and a3; a3 and a4; etc in Column B

However, when I put e.g. a4-a5, it shows result ########. The answer should be 0001

How can I correct it?

 

[Tetra201]

The answer is -1, not 1. Do you want do display negative minutes?

 

[learning_grexcel]

No, even if negative, it should be positive. Thanks

 

[Tetra201]

Two more questions:
1) If you format cell A1 as "General", what does it display?
2) What is the result of the following formula =ISNUMBER(A1)?