Chapter 22 Page 15 - Monthly Annuities

Hi a very basic question, it's been a while since I have done CT5 and I don't have the notes anymore.
In the example on page 15 Chapter 22 in the CMP, how does the monthly immediate annuity (age 42) simplify to an immediate annuity (age 42) - 11/24. I can't work out where the "- 11/24" adjustment comes from.

Thanks

 

I think you'll find that formula in the orange tables.

 

Thank you!