Puzzles - Number puzzles

Answer

:

57

Explanation

:

As you work down the column, numbers follow the sequence of Square Numbers from 16 to 81, subtracting 4, then 8, then 12 etc.

Answer

:

1

Explanation

:

Splitting the diagram into 3 smaller triangles, with 3 circles each, the sum of the numbers in each smaller triangle is always 21.

Answer

:

69

Explanation

:

Starting at the top and working down, double each number and subtract 5 to give the next number down.