Skimming through the active threads, I initially read this as Grans who argue
perish the thought!
They both want your attention - could you suggest that if they are "good", you will give each of them an hour of your time to choose an activity to do with you from a list- ie drawing together, crafts, making cake,let them apply nail varnish on you etc, making papier mache ornament?. The other one could do it too - provided they were good. Then later in day it would be their turn.Have a clock showing time of each session. If not behaving well, ignore (well try) and sit and read etc.
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The best thing my boys loved when young was my undivided attention, as I also worked and was very busy.