# Tough Sequence Riddle: If, 1 + 2 + 3 = 9 Then 5 + 6 + 7 = ?

Toughest Riddle ever.

If you are able to solve this you are a super-genius.

If,

1 + 2 + 3 = 9

2 + 3 + 4 = 2

3 + 4 + 5 = 8

4 + 5 + 6 = 9

Then,

5 + 6 + 7 = ? If you can guess what comes next in the sequence you will be among the top 2 % of people who can actually solve this riddle.

Challenge your brains and start working.

The logic behind the riddle is as follows;

For explanation sake we consider the following euation;

a + b + c.

Now looking at the equations in the sequence, the first step is;

a + b + c = (ca,cb)

The second step is to keep adding the digits of the resultant number till it reduces to a single digit number.

Let’s try the first equation (1 + 2 + 3) with this logic for better uinderstanding

So applying first step we get;

1 + 2 + 3 = [(3 x 1),(3 x 2)] = 3,6 = 36

Applying 2nd step we get

3 + 6 = 9;

Similarly the same logic is true for all other equations

2 + 3 + 4 = (4 x 2),(4 x 3) = 812 = 11 = 2

3 + 4 + 5 = (5 x 3),(5 x 4) = 1520 = 8

4 + 5 + 6 = (6 x 4),(6 x 5) = 2430 = 9

So we can solve the last one to get the answer as;

5 + 6 + 7 = (7 x 5),(7 x 6) = 3542 = 14 = 5

## 5 Replies to “Tough Sequence Riddle: If, 1 + 2 + 3 = 9 Then 5 + 6 + 7 = ?”

1. Hafeez says:

step 1: (A+B) x C… It results in xyz. step 2: Add (x+y+z) and get result. Repeat step 2 until single value is obtained.
For example for the required case (5+6) x 7= 77 which is equal to (xy) in first step. Now adding 7+7 = 14 (similar to x + y in second step) adding (repeating step 2) 1+4 = 5. So 5 is the answer….

2. Kavita samson says:

1+2+3=6+3=9
5+6+7=18+3=21

3. Sharmili says:

4. HEMANG SHARMA says:

Or we can solve it by doing following operation-