In this post I will briefly explain the challenges and possible solutions to this problem.
- I found half of a dinosaur’s bones buried in the ground. I found 9 bones. How many bones did the dinosaur originally have?
Most children will be confident with the idea of finding a half (two equal groups) using their mental maths skills or by separating out a pile of counters into two equal groups. However the challenge in this problem is that 9 cannot be shared into two equal groups so we must need to do something else, and this is were children can get stuck.
The solution to this problem is to realise that the 9 is what I ended up with, not how many I started with.
As we are also told that this is half, there must be another equal group of 9 bones in the sand. By counting up all of the bones we can now see, we get the answer 19.