Grade 6 Mathematics · Unit 10: Math Is...Standard MPP.7

Lesson 10.310.3 Small Group · Group 1

Start hereWords, worked example, and sentence starters

Name Date Period

Learning target With my small group, I can use patterns and relationships to make sense of the Tower of Hanoi puzzle and think logically about its solutions — one step at a time, with support.

Start hereWords for this lesson

Read each word before you begin. Say it out loud.

WordWhat it meansExample
puzzleSpanish: rompecabezas A problem designed to be played with — it has rules, a goal, and room to imagine solutions. Tower of Hanoi: three rods, a stack of discs, and two rules.
patternSpanish: patrón Something that repeats or changes in a predictable way. Circle, square, triangle, circle, square, triangle …
pattern ruleSpanish: regla del patrón A rule that tells you how to get the next value in a pattern from the one before it. 1 → 3 → 7 → 15: the rule is “double it and add 1”.
predictSpanish: predecir To say what will happen before it happens, using a pattern or reasoning. We counted towers of 1, 2 and 3 discs. Reach PAST them: the rule says 5 discs takes 31 steps — before moving one.
organizeSpanish: organizar To arrange information — often in a table — so patterns become easier to see. Discs 1, 2, 3 in one column and steps 1, 3, 7 in the next.

How it worksWorked example

These numbers are not on your problems. The steps are. Follow them with your own numbers.

Move a 2-disc tower from Rod A to Rod C. Move one disc at a time. Never put a big disc on a small disc. What is the least number of moves?

  1. Picture the goal first.
  2. Move the small disc out of the way: small: A → B
  3. Move the big disc to Rod C: big: A → C
  4. Put the small disc on top: small: B → C
  5. A 2-disc tower takes 3 moves. A 1-disc tower takes only 1 move.

Now you trySame steps, your turn

The steps are the same as the worked example. The numbers are yours. Do the work.

Discs: 1, 2, 3. Steps: 1, 3, 7. Find the pattern rule. Use it to find the steps for 4 discs and 5 discs.

Answer:

Say it and write itSentence starters

Finish each sentence out loud with a partner. Then use them in your writing.

Word bank puzzlepatternpattern rulepredictorganize

Watch outA common mistake

Doubling the previous number of steps but forgetting to add 1 — answering 14 instead of 15 for four discs, or 30 instead of 31 for five.

Grade 6 Mathematics · Unit 10: Math Is...Standard MPP.7

Lesson 10.310.3 Small Group · Group 1

Group 1Supported practice

Mastery check☐ Exceeds☐ Meets target☐ Needs practice
Name Date Period

Learning target With my small group, I can use patterns and relationships to make sense of the Tower of Hanoi puzzle and think logically about its solutions — one step at a time, with support.

  1. 1Complete each step, then write the final answer.
    PartMoves
    2 discs off?
    big disc?
    2 discs back?
    Three parts solve a 3-disc tower.

    A 2-disc tower takes 3 moves. To move a 3-disc tower, move the top 2 discs off. Then move the big disc. Then move the 2 discs back on top. How many moves in all?

    1. 1How many moves does it take to move the top 2 discs off?
    2. 2How many moves for the big disc?
    3. 3How many moves to put the 2 discs back on top?
    4. 4Add the three parts. How many moves in all?
    Final answer:
  2. 2Complete each step, then write the final answer.
    PartMoves
    3 discs off?
    big disc?
    3 discs back?
    The top 3 discs move off, then back.

    A 3-disc tower takes 7 moves. Use the same three parts to solve a 4-disc tower. How many moves does it take?

    1. 1How many moves does it take to move the top 3 discs off?
    2. 2How many moves for the big disc? For the 3 discs back?
    3. 3How many moves in all?
    4. 4Write it with the rule “double, then add 1.”
    Final answer:
  3. 3Complete each step, then write the final answer.

    A pattern starts at 4. The rule is “double, then add 1.” What is the 3rd number in the pattern?

    Show your work

    Hint Use the rule on 4 to get the 2nd number. Then use the rule again.

    Final answer:
  4. 4Complete each step, then write the final answer.
    DiscsMoves
    663
    7?

    A 6-disc tower takes 63 moves. How many moves does a 7-disc tower take?

    Show your work

    Hint Use the rule “double, then add 1” on 63.

    Final answer:
  5. 5Complete each step, then write the final answer.

    Lee solves tower puzzles. A 7-disc tower takes 127 moves. Lee makes 1 move each second. How many seconds does an 8-disc tower take him?

    Show your work

    Hint First find the moves for 8 discs. Each move takes 1 second.

    Final answer:
  6. 6Complete each step, then write the final answer.

    A 4-disc tower takes 15 moves. Sam says a 5-disc tower takes 16 moves, because it has 1 more disc. Is he right? How many moves does it take?

    Show your work

    Hint Sam only added 1 move. The rule says to double first.

    Final answer:

Explain your thinkingWhy does one new disc double the old moves, then add 1? Talk about moving the small tower off and back.

Sentence starter First I move the small tower off, which takes ___ moves. · The rule is “double, then add 1” because ___.

How did it go? ☐ 4 · I can teach it☐ 3 · I've got it☐ 2 · I need a hint☐ 1 · I need help