Multiplying number patterns, step by step

Some sequences do not add the same amount — they multiply by it, so they grow fast.

The question

1, ?, 9, 27

1?927
1?927
1?927
13927
  1. Find the rule first, from two numbers you can actually see — never from the gap.
  2. 9 to 27 is × 3. One pair is only a guess — the number after the gap will confirm it.
  3. Now apply it to the gap: 1 × 3 = 3.
  4. Check it against the number already after the gap: 3 × 3 = 9, which is what is there. The missing number is 3.

How it works.

  1. 01

    Find the rule first, from two numbers you can actually see — never from the gap.

  2. 02

    9 to 27 is × 3. One pair is only a guess — the number after the gap will confirm it.

  3. 03

    Now apply it to the gap: 1 × 3 = 3.

  4. 04

    Check it against the number already after the gap: 3 × 3 = 9, which is what is there. The missing number is 3.