Last survivor payable monthly for term n

A question I have come across requires us to work out

but I can't seem to find any texts that explicitly state how to remove (12), I was told it's the same as without it, so I can ignore it, but then would the (m)thly conversions for most other annuities hold so that it can be written as the the SL + SL - JL, then convert those normally by subtracting (m-1/2m) for each one?

Edit: Those annuities (the SL + SL - JL) should be annuities due

 

I'm afraid this is quite a complicated one to work out! Subtracting 11/24 from temporary annuities doesn't correctly allow for the monthly payments. That approximation only works on whole life annuities, so we need to put the expression in terms of whole life annuities before we can use the (m-1)/2m approximation, ie:

 

Thank you, I’m fine with working out the adjustments for monthly payments for term annuities, I was just unsure whether or not we could break it into SL + SL - JL then adjust, since my lecturer said you can essentially ignore the monthly part and leave it as annually, but I feel like maybe he mistook my question.