Please help as I'm stumped!
1) (50{20}10). (80{30}20)
(40{?}8)

2)
(20{22}9). (30{30}15)
(25{?}10)

3)
(4{11}3). (9{13}6)
(11{?}4)

Any tips much appreciated

I’m not going to assume you know what to do with these, so apologies if you do.
The numbers either side of the bracket can be mathematically used to get the middle number. The operations required are the same for all three, so once you figure out how the two known ones work you can work out the unknown one.

There’s only one or two arithmetic operations to get these.

So only -+/x are used plus halving/doubling.

The first one requires subtraction and halving, to get you started.

Btw practice is the key for these. DD hated them to start with but with practice she could spot them straight away.

6 years later and she hasn’t lost the knack either. I’ve just checked.

Thinkers
Now I understand!
Thank you so much

Hi, does anyone know what question type this is please? None of my books have these in and I'd like to search for them.

Thanks

I think they might be 18 or K

viewtopic.php?f=3&t=3740

They are certainly in One of the the SD verbal reasoning techniques and practice books, but there’s 4 and I don’t know which book they are in.

Thanks Tinkers. I'll take a look. They came up in my DDs mock but haven't seen them in any of our books. Thank you again.