Puzzles - Number puzzles

55.
Answer
:
9
Explanation
:
Working from left to right, the sum of the two smaller numbers on each triangle equals the third number.

56.
Answer
:
6
Explanation
:
The number in the centre of each star equals the average of the surrounding 5 numbers.

57.
Answer
:
43
Explanation
:
In each triangle, multiply the lower two numbers together and add the upper number to give the value at the centre.