You can apply the Format Cells feature to only show the positive numbers in a selection in Excel. Please do as follows:

1. Select the range you will hide all negative numbers, right click and select Format Cells from the context menu. See screenshot:

2. In the Format Cells dialog box, please click Custom in the Category list box, type the format code 0;[White]0 in the Type box, and click the OK button. See screenshot:

Notes:
(1) The Format code 0;[White]0 will show all positive numbers as whole numbers. If you need to keep decimal places, please change the format code to 0.00;[White]0.00.
(2) In the format code 0;[White]0, White means to show negative numbers in white. If the cell fill color is different, please change White to the fill color.    

Now you will see only positive numbers are shown in the selected range. See screenshot:

Quickly change all negative values to zero or positive values in Excel

In some cases, negative values may be invalid, and you have to change all negative numbers to zero, or change all negative numbers to their absolute values. With Kutools for Excel’s Change Sign of Values utility you can get it done easily.

You can also apply the Conditional Formatting feature to only show the positive numbers in a range. Please do as follows:

1. Select the range you will only show the positive numbers, and click Home > Conditional Formatting > New Rule. See screenshot:

2. In the New Formatting Rule dialog box, please:
(1) Click to highlight Use a formula to determine which cells to format in the Select a Rule Type list box;
(2) Type =A1<0 (A1 is the first cell in the selection) in the Format values where this formula is true box;
(3) Click the Format button. See screenshot:

3. In the Format Cells dialog box, go to the Font tab, please specify the font color same as cell fill color in the Color drop-down list. See screenshot:

4. Click the OK buttons successively to close both dialog boxes.

Now you will see only positive numbers are shown in the selected range. See screenshot:

For example, I have a table as below screenshot shown, now I want to calculate the totals in the Column E but hide all negative calculation results:

Type the formula =IF(SUM(A2:D2)<0,"",SUM(A2:D2)) in the Cell E2, and then drag the AutoFill Handle down to fill in the Column E.

Now you will see all totals are calculated in the Column E, and only positive calculation results show. See screenshot:

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