I am an educated mother , and yet I cannot help my child with her grade 3 math! We have worked on it both together and separately for about 4 hours. The question is to use the numbers 1 through 9. They are to be placed on lines, and each group is to add up to 11. The trick is that the first 2 numbers used add to 11, then lines 2, 3 and 4; then lines 4,5 & 6; then lines 6,7 & 8; and then lines 8 and nine (it is really hard to describe. In the book, is shows circles making each group). The lines are all horizontal, and lined up to each other like:_ _ _ _ _ _ _ _ _My daughter has been in tears and I'm about ready to pull my hair out.
Thanks for your help! Jayne
I understand the puzzle correctly, 837164529 should be an answer.
I started by noticing that the line alternates between numbers in one group and
numbers in two groups: (one)(two)(one)(two)(one)(two)(one)(two)(one).
I asked myself whether small numbers should be in the spaces in two groups,
or big numbers should go there.
This is answered as follows: If you add the numbers from 1 to 9 you get 45,
but if you add the five groups of 11, you get 55, having counted twice
the numbers in the (two) spaces. So, the number in the (two) spaces must only
add up to 10, and using 1, 2, 3, 4 is the only way to go.
From there it is a little bit of fiddling: I notice that 1 cannot go in the first
(two) space, because in the first group I would need 10 more to add up to 11.
So, I may as well put 1 in the second (two) space. Can I put 2 in the first
(two) space? Well let's see...