9 x 9 + 9 = 90
8 x 8 + 8 = 72
7 x 7 + 7 = 56
6 x 6 + 6 = 42

3 x 3 + 3 = 12

I agree with Randy. It's 12.

I did it this way--
9x8=72
8x7=56
7x6=42
6x5=30
5x4=20
4x3=12

Assuming there is a 5 and a 4 in the table Reggie would be correct, but there isn’t.
Going strictly by the numbers in the table I’ll stick with 18.

In fact, 9 = 90 is an assumption as well because we are expected to assume there is a 10 above the 9 in the sequence.



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Exactly. The clue is the very first line. That tells you to use "logic" to compute the answer.

I also approached this as did Reggie, but when the implication was that it was incorrect, I went back and looked at the numbers as if there were no others.

So, assuming this: the progression from 6 to 3 is that 3 is half of 6. Following this then 3.5 is half of 7. So, if the numbers are multiplied, 3 times 3.5 is 10.5.

Hey, when you're told your wrong you have to keep trying...what can I say?:crying:

My vote is 12

My thought process
9-90 - 18
8-72 - 16
7-56 - 14
6-42 - 12
5-30 - 10
4-20 - 8
3-12 - 6
2-6 - 4
1-2 - 2
0-0

I'm with Reggie and Randy on this. It would seem each equation is on it own and not linked. In each the first number is multiplied by a number one higher than itself so:
9x10=90
8x9=72
7x8=56
6x7=42
3x4=12

I have no doubt it is 12. I'll have to reread the thread to see where the 18 comes from.