Cell Data Format whole column to 1 or 2 decimal places

This is how "auto" decimal places works.

5/14 = 0.3571... It requires all the decimal places it has to provide you the result.

5/10 = 0.5 It requires one decimal place to give you the exact result.

10/10 = 1 It requires no decimal places to give you the exact result.

If you want a consistent number of decimal places, change them all from "auto" to whatever number of decimal places you want. Note that this only changes how the number is displayed, it does not affect the value in the cell. The value of the calculation 5/14 will still be 0.3571... in the cell even if it is being displayed as 0.36. If you want the value to actually be rounded to a specific number of decimal places, use the ROUND function (or one of the other rounding functions).

It depends on the results in the cell. If the result only requires 2 decimal places, "automatic" gives it 2 decimal places. If it requires 3 it gets 3. If it requires 15 or more it gets as many as it can get (the precision is limited to 15 total digits so "15 decimal places" may end with a few zeros).

If you want two decimal places, set it to 2 decimal places.

As noted by Badunit, "Automatic" displays as many places after the decimal as needed to show the result of the calculation, up to limit of 15 significant digits.

In the base 10 system, division by 7 (or by a multiple of seven) of any number that is not itself a multiple of 7 has a decimal result that never finishes. Note repeating group '571428' in all of your 14 MPG column examples, except for 2.5, the result for 35 (a multiple of 7) miles.

Regards,

Barry

Part of the alternation between 'one' and 'no' decimal places in your '@ 10.0 MPG' column is due to your choice of numbers in the 'Travel Miles' column. division of whole numbers by 10 will always produce an exact value requiring one or fewer decimal places to express.

Regards,

Barry