These number puzzles are designed to challenge your brain and improve your problemsolving skills.

1. Test Your Logical Skills with Math Puzzles: Number Riddle 
In each puzzle, there are set of numbers. These numbers connect to each other with some logical pattern. Your challenge in each number riddle is to crack this hidden logical or mathematical code. Once you've cracked the code, you'll be able to determine the missing number that replaces the question mark in each puzzle.

2. Test Your Logical Skills with Math Puzzles: Number Riddle 

3. Test Your Logical Skills with Math Puzzles: Number Riddle 

4. Test Your Logical Skills with Math Puzzles: Number Riddle 
2 comments:
Q1)
Answer is 8
(a*a)+(d*d)=bc
3*3+4*4=25
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And so on
answer can be 2
coz if you add the diagonal numbers of each circle and subtract them the resultant follows a series
1st CIRCLE
77=0
2nd CIRCLE
87=1
3rd CIRCLE
1311=2
and so on
give it a try you'll get 2 in that blank space