I'm not sure where you are going with A1,B1,A22,C17,but in these cells  you
can put a conditional formatting based  on the formula =DAY(TODAY())

So for A1 check if the formula is equal to 1 and then set the colour to
yellow.

For B1 check if the formula is equal to 2 ..

To elaborate , check out "Conditional Formatting" in
Excel Help. It's on the Format menu.



In your case, you'd go to cell  A1, hit Format/Conditional Formatting.,
select "Formula Is" (instead of "Cell Is") and enter =DAY(TODAY())=1, select
Format, go to the Patterns tab, and select Yellow as the background  color,
hit OK and OK.



Then go to B1, and do the same thing with "Formula Is" set to
=DAY(TODAY())=2, with Yellow pattern.

Go to A22, and do the same thing with "Formula Is" set to =DAY(TODAY())=3,
with Yellow pattern.

And go to C17, and do the same thing with "Formula Is" set to
=DAY(TODAY())=4, with Yellow pattern.

Etc.



Does this make sense? Pretty cool feature.