Unit 1 · Patterns and Sequences

Start at 53 — Odd +1, Even ÷2, 5 Times?

Lesson 6 of 6

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About this lesson

Start at 53, apply 'odd→+1, even→÷2' five times: 53→54→27→28→14→7. The sequence alternates between adding 1 (to make odd numbers even) and halving (to reduce even numbers). Students who apply the rule only 4 times land on 14 (option C-ish) — counting steps carefully is critical.

Chapters

0:00Introduction
0:23The Question
0:59Step 1 – Starting with the initial input
1:25Steps 2 and 3 – Consecutive halving transformations
1:54Steps 4 and 5 – The final calculation cycles
2:27Exam strategy — the step-counter audit box
3:17Confirming the final option

Question

Shawn starts with the number 53 and follows this instruction five times:

  • If the number you have is odd, add 1, or if it is even, divide by 2.

After following the instruction five times, what number does Shawn have?

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Lesson 5
Up next: Unit 2 — Number Theory

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