Keep them busy!
When I was a child my mum had a special talent of coming up with 'projects' for me to do that would keep my occupied by myself or with my brother for hours. I absolutely loved it at the time and now I understand that this was a pure genius way of getting me out of her hair so she could get on with things. These are some brilliant ways to get children ages 7+ out of the way so you can work/rest, whilst simultaneously encouraging their creativity and inventiveness!
1. Make a magazine or comic. All they need is some paper folded into a little book stapled together and some colouring pens/pencils. More tech-savvy older kids could have a go on the computer
2. Create a radio show or podcast. An old tape recorder would be brilliant, but equally a recording program on a computer or phone would do, for example the garage band app.
3. Scavenger hunt in the house/flat/garden. I normally do this for a prize to get them extra motivated. Make an extensive list of things they need to find and bring to you. If you are in the park or have a garden a nature scavenger hunt works well, e.g. "a leaf, 3 stones, an insect, a feather... etc" but a household equivalent is just as good, "something boring, something fun, something delicious, something shiny....". This will keep them busy and out of the way for ages!
4. Making slime. Once they know how to do it, mosts kids 6+ can be left alone to make this by themselves (if they make the slime correctly it can also be really easy to clean up afterwards as it peels off surfaces). I go for the classic recipe of contact lens solution, PVA glue, food colouring and shaving foam. But make sure you get the right contact lens solution (it must contain BORIC ACID, I recommend Bausch and Lomb or ReNu) or you will be faced with a very disappointed child! How to make it: https://www.youtube.com/watch?v=_cIbDffLQtk. There are also thousands of variations - researching slime online can be a fantastic time-absorbing activity for children as well.
5. Making 'movies' with a phone camera. I encourage children to create a script/dialogue/some sort of plot and to use lots of props. I leave them to plan their film and then come back to be the camera person for them when they are ready. Watching the films after and laughing over the mistakes and outtakes is normally the funnest part of this activity.