Can someone explain this / answer it? 18 POINTS + Brainliest

Answer:
I believe it is because he has exhausted all the different ways to use the 18 m he has. Look below.
Step-by-step explanation:
He has 18 m of wood and he has done:
8+8=16 1+1=2 16+2=18
7+7=14 2+2=4 14+4=18
6+6=12 3+3=6 12+6=18
5+5=10 4+4=8 10+8=18
So he has no more ways to use the 18 m of wood and has exhauseted all the ways.
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