Struggling with Excel? How to Highlight Specific Numbers in Your Chart

Hi, can anyone help me in Excel? What formula should I use if:

457812
852147
458561
147248

I want to identify the numbers outside the chart. The answer is 3 and 9.

1) Which formula should I use? Please teach me.
2) From this chart, I want to target the number as shown below.
Target number: 5
457812
852147
458561
147248

When the target number is input, it should be highlighted in red on the chart.

3) Or should the cell be highlighted in red on the chart? Please teach me. Thank you in advance.

Just check whether the attachment is of any use to you.

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I have corrected the spelling of "whether" and rephrased the sentence slightly for better clarity.