Please, how to color cells regarding formula element?

Hello!
Please, I have columns I, J, K, L.

In I column I have values from 10 to 100 (10,20,30…100)
In columns J k and L iI have 3 formulas each containing value from I column, from the same row.
How can I color all the cells at once red containing I value less them 50 and blue greater or eqal 50?

I have idea hov to do it column by column.
My question is if we can find a way to do all the tablein “one step” and how?

MANY THANKS!

select all 3 columns
do Format > Conditional Formating > Condition
set there the color condition you need