I’m tall when I’m young, and I’m short when I’m old. What am I?

Can you replace the question mark with the correct number in the below table sequence?

Pronounced as one letter,
And written with three,
Two letters there are,
And two only in me.
I am double, I am single,
I am black blue and grey,
I am read from both ends,
And the same either way.

Prove that the below maths equation is true.

8 + 8 = 91

I’m orange, I wear a green hat and I sound like a parrot. What am I?

Can you find the least possible number such that

If the number is divided by 3, it gives the remainder of 1;
If the number is divided by 4, it gives the remainder of 2;
If the number is divided by 5, it gives the remainder of 3;
If the number is divided by 6, it gives the remainder of 4.

Replace the (?) with the correct mathematical signs to make the expression equal to 59.

18 ? 12 ? 4 ? 5 = 59

Can you spot the hidden girl in the picture below?

What runs around the whole yard without moving?

Can you count the number of triangles in the picture below?