Multiple Conditional Formatting Rules

Multiple Conditional Formatting Rules

When I use multiple conditional formatting rules how do I control the execution order? 

e.g. If Rule1 says to color fields with less than 700 as Red and Rule2 Says to color less than 800 as Red will the order of execution matter and how can I control it to achieve the desired outcome 

i,e, 

800+ No formatting
700 to 800 Yellow
<700 Red