Note: it's important that CF formulas be entered relative to the "active cell" in the selection, which is assumed to be B4 in this case.
Once you save the rule, you'll see only values that are integers (whole numbers) highlighted.
How this formula works
The MOD function returns the remainder after division. With a divisor of 1, MOD will return zero for any whole number.
We use this fact to construct a simple formula that tests the result of MOD. When the result is zero (i.e. when the number is an integer) the formula returns TRUE, triggering the conditional formatting.
When the result is not zero (i.e. the number has a decimal component, and dividing by 1 leaves remainder) the formula returns FALSE.
Excel contains many built-in "presets" for highlighting values with conditional formatting, including a preset to highlight unique values. However, if you want more flexibility, you can highlight unique values with your own formula, as explained in...
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