← All PI Flashcard Decks

Number Series Problems Flashcards

7 cards from real PI practice questions. Tap to flip, then mark Knew It or Still Learning — missed cards come back until you master them.

Read the first 7 Number Series Problems flashcards as text
  1. What is the next number: 120, 60, 20, 5, ___?

    Answer: 1.25

    Divide by 2, then by 3, then by 4 — the next step divides by 4, so 5 ÷ 4 = 1.25.

  2. Find the missing number: 3, 6, 11, 18, ___, 38

    Answer: 27

    Differences are 3, 5, 7, 9, 11 — odd numbers, so 18 + 9 = 27, and 27 + 11 = 38 confirms it.

  3. What comes next: 64, 32, 16, 8, 4, ___?

    Answer: 2

    Each term is halved, so 4 ÷ 2 = 2.

  4. Complete the series: 2, 6, 18, 54, ___

    Answer: 162

    Each term is multiplied by 3, so 54 × 3 = 162.

  5. What is the next term: 10, 10, 20, 60, 240, ___?

    Answer: 1200

    Multiply by 1, 2, 3, 4, 5 — the next multiplier is 5, so 240 × 5 = 1200.

  6. Find the missing number: 15, 13, 16, 12, 17, 11, ___

    Answer: 18

    Two interleaved sequences: 15, 16, 17, 18 (+1) and 13, 12, 11 (−1), so the next is 18.

  7. What comes next: 0.5, 1, 2, 4, 8, ___?

    Answer: 16

    Each term doubles, so 8 × 2 = 16.