We had over 80 solutions sent in for this challenge, thank you. Here are just a few showing the variety the pupils offer.

Francesca sent in a spreadsheet as follows;

Jack sent in his result as pictures.

Mia sent in a spreadsheet in this way.

Christabel wrote as follows;

What I did before: I first drew 20 cakes and then I put icing on the second one, cherries on the third one and then choc buttons on the next one and then I missed one and I kept on doing that until I got to the end.

What I'm doing now: I made cakes and then labelled them 1,2,3 ...Then I put icing on the ones that are in the 2 times table. I put cherries on the ones in the 3 times table and choc buttons on the cakes if they're in the 4 times table. Then I would count how many toppings they have.
Q1. 1,5,7,11,13,17,19.
Q2.Number 12 did which had icing on, cherries on and choc buttons. Which means that there was only one.

Zahrah wrote it out in this way;

1st biscuit= nothing
2nd biscuit= Icing
3rd biscuit= Cherry
4th biscuit= Chocolate Button, Icing
5th biscuit= Nothing
6th biscuit= Cherry, Icing
7th bicuit= Nothing
8th biscuit= Chocolate Button, Icing
9th biscuit= Cherry
10th biscuit= Icing
11th biscuit= Nothing
12th biscuit= Chocolate Button, Icing, Cherry
13th biscuit= Nothing
14th biscuit= Icing
15th biscuit= Cherry
16th biscuit= Chocolate Button, Icing
17th biscuit= Nothing
18th biscuit= Cherry, Icing
19th biscuit= Nothing
20th biscuit= Chocolate Button, Icing

7 Biscuits had no decorations.
1 got all three decorations.

Adam sent in this chart;

Eboselumen described her working as a set of instructions;

you label the biscuits 1-20
you draw the icing on 2, 4 6, 8, 10, 12, 14, 16, 18, 20
the cherry on 4th, 8th, 12th, 16th, 20th
the chocolate button on 3, 6, 9 , 12, 15, 18
so 5 cakes did not get anything
nos 5, 11, 13,  17,  19
it's simple, the logic is that only prime nos can have nothing so all numbers that are a multiple of either 2, 3, 4 will have something on it, the only one with everything on it is 12 which is a multiple of all three nos

and finally Lorne used a spreadsheet to show her working;

Well done all of you! This may be a help for teachers to see the variety of approaches that we can start to expect from pupils.