Include a value from one cell within text of another cell.

Regarding the question when user enter data in cell B4, the cell B5 will show text such as " X is not a valid entry. Please enter the correct pair number." for entry of 25~150 (X is the enter number). You can use the formula below at cell B5:

You can also use Data Validation at Data, Data Validation by setting Setting below.

You can also set message box to display by setting Error Alert below.

When the number 25 to 150 is enter, a message box and text is displayed as below.