On four worksheets in a workbook, the following cells have
theese typical values, and text:

Cells Value Name
M15/M47/M79 - 110 - Chart Max
M16/M48/M80 - 100 - Target
M18/M50/M82 - 75 - UCL
M22/M54/M86 - 70 - LCL
M26/M58/M90 - 60 - Op Zero
M29/M61/M93 - 45 - Chart Min

M15 must always be greater than M16, M16M18, etc. M47
must always be greater than M48, M48M50, etc. Same for
the M79 cells. What would the code be and where do I put
it) where a message comes up indicating the error? For
example: if M22 = 70, and M18 = 75, the message says
that "UCL cannot be greater than LCL", the user clicks ok,
and then fixes the error.
Would I put the code in Module1?

Thanks, Phil