Thank you to everybody who sent in their ideas about this task. Adam, Appin, Maya, Sol and Suria from Parklands School, Albany, Australia sent in this solution:

We wrote the numbers from the question on the metre line marks to make it easier to see and remember. We also used a ruler to align the mouths of the animals with the closest marking. We were then able to count the difference using the marks like a number line. We found these answers:
1. The seagull is 4m above sea level
2. The crab is 9m below sea level (or -9)
3. The shrimp is 2m lower than the shark
4. The eel is 7m below the surface (or -7m)
5. We thought this was the same as question 1, so it is 4m.
6. The seagull's beak is 7m higher than the seahorse's mouth.

This is very clearly explained. Take a look at Adam, Appin, Maya, Sol and Suria's full solution to see how they annotated the picture.

Myla and Farah from Maltman's Green School in the UK both drew bar charts to represent the distances of the different animals from the sea level. Have a look at Myla's bar chart. Can you see why Myla has used the calculation 4+3=7 to work out the answer to our sixth question?

We also received correct solutions from: Oisin from Ballyhack National School in Wexford, Ireland; Rayya from British School Al Khubairat in the UAE; Ahmed and Dhruv; Hannah from Burley and Woodhead C of E Primary in the UK; Astrid from High March School in the UK; Toby and Elsie from Shirland Primary in the UK; and Imeth, Aseel and Safura from Pristine Private School in the UAE. Thank you all for sharing your thoughts with us.

Some children suggested other questions that could be asked about this picture. Farah asked:

How far is the crab's head to the top of the lighthouse? 15m

Hannah asked:

How many metres is the very top of the lighthouse to the sting ray?

Astrid from High March School in the UK also came up with some questions of their own. Take a look at Astrid's full solution to see their questions.

Can you answer all of these questions?