Is it me or is this a RIDICULOUSLY hard maths problem for a 7 year old?

[Spidermama]

New school. He's in year three and this is the homework problem he has been given.

Keiron has three cats. Each is a different weight.
The 1st and 2nd weigh 7kg together.
The 2nd and 3rd weigh 8kg together.
The 1st and 3rd weigh 11kg together.

What is the weight of each cat?

Surely the point of this exercise is to test their problem solving skills/techniques? Ds in yr 2/3 was doing lots of work like this; to assess how his maths brain worked/how methodical his approach was/what attempts he might make to solve it. I don't think the point is whether they can do but how they might try to do it?

Says on the link these problems are fore able pupils in years 3 & 4 so can't see why they're being given to year 2 children.

The child in the OP is in Y3, and some children are very able mathematicians.

I sent this to my DS (Y5) just to see what methodology he would go for - he has just emailed me back the answer, but not told me how he went about it

DS (year 4, not boasting but v. good at maths) couldn't do it when i just asked him - although he did throw out 5 & 6 before he gave up.

Its not fun when the child can't do it no matter what and its their homework, but I wish more schools were willing to challenge the more able children like this.

I do honestly talk to DS other than on email, but this specific conversation has been with his school email - in answer to my question about how he went about it, he said "you do it backwards"

I now understand why his teachers sometimes find it an uphill battle to get him to show his working.