Conditional Formatting Based on Multiple Cells Added(Sum) Values + Possible VBA?

[internct]

Hi,
So I am doing inventory and one column is for inventory on order and inventoy in stock.

A B C D
0 4 4 6

When A+B is <=C, I want either the entire row to highlight or cell A1,B2,C3,D4. C is the minimum number of inventory and D is how much to order when they've reached the minimum.
If it's possible, I also want a popup message reminding people that A1 and B1 equals to C,so they should order D quantity

 

[etaf]

for 2007, 2010 or 2013 excel version
Conditional Formatting


Highlight applicable range >>

Select the range - for example A2:D10000



Home Tab >> Styles >> Conditional Formatting
New Rule >> Use a formula to determine which cells to format
Edit the Rule Description: Format values where this formula is true:



=($a2+$B2) < = $C2



Format… [Number, Font, Border, Fill]
choose the format you would like to apply when the condition is true
OK >> OK