# Pattern 1 -- Numbers

Fill in the missing number: 10, 30, 60, 01,__, 12
Use a bit of lateral thinking.
And math.
Also, I do know the answer. Just giving the question as a teaser.

Let's try reversing the digits:

01, 03, 06, 10, __, 21

Then I see this:

01 + 2 = 03
03 + 3 = 06
06 + 4 = 10
10 + 5 = 15
15 + 6 = 21

As 15 is the answer when the digits are reversed, the missing number in your sequence is 51.

• Yep. That is the answer. Good Job! Now I need to try and get other patterns...
– user360
Jul 27 '14 at 1:32

This answer is silly but in this sequence, there exists 4 zeroes and 3 ones. So it follows, there should be 2 twos, 1 three, 0 fours, -1 five, and -2 sixes. But if you take absolute value, we have 2 sixes. Since there is only one two and one six already, the missing bit is 26. It cannot be 62 because let's say, we must have one of the same digits in whatever pair, reversed. Again, just a silly observation.

• It was already correctly answered six years ago though. Apr 9 '20 at 17:19
• Yes. I know. Just wanted to contribute.
– Ash
Apr 9 '20 at 17:21