Two numbers add up to 20. One of them is 6 more than the other. Half of 20 is 10, and 10 and 10 is wrong — but it is exactly where the answer starts.
If they get stuck
The answer key prints on a separate page.
An even split satisfies the total and ignores the difference. Moving half the difference from one side to the other fixes that without disturbing the total: 10 and 10 becomes 13 and 7, which still adds to 20 and now differs by 6. Half of the difference, not the difference — that halving is where the question lives, and it is the step almost every child skips the first time.
The arithmetic is grade-2 work: halve a number, add, subtract. Nothing here is above grade level, which is the point of this whole tier. What makes it a challenge question is that a child cannot begin the moment they finish reading it — there is something to work out before the first sum.
One question from a sheet like this one, worked a step at a time — with a sentence saying what just happened and why.
Sum and difference puzzles, step by step