Thank you for all your correct solutions. Three were particularly well explained.

Zeenat from St Margaret's Preparatory School wrote:

If the triangle is on the blue side then I found three ways to
post it into the black hole. I used the dot to help me. I moved the
dot to the three different corners of the triangle by turning
the triangle and that is how I found three ways of posting the
triangle into the black hole.

If I had to post it on both sides (blue and yellow) then there
would be $6$ ways of doing it because I know that $3$ ways plus $3$
ways is equal to $6$ ways of doing it.

Mia from St Teresa's said:

I found six ways, three blue and three yellow. The dot was at the top, then on the left and then on the right.Amy from St Alban's Roman Catholic Primary School told us:

There are six ways.

The first you can just put the triangle in - $1$ way.

Then flip over the triangle to yellow - $2$ ways.

Then you turn the triangle so that the point is at the other
corner - $3$ ways.

Turn the triangle as in number $3$ and flip the triangle
yellow - $4$ ways.

Keep turning until the point is at the last corner - $5$
ways.

For the last time, turn it as in number $5$ and flip it yellow
- $6$ ways.

That is all of the ways.