Operations & Word Problems

Problem

Reverse the moves to recover original

Some original shape was flipped upward 7 times and then turned 90 degrees clockwise, giving the figure shown on the right (it looks like the numeral 4). We must work backward to draw the original shape.
Draw original After moves
Geometry
Your answer
How to solve
Strategy Work Backwards — We are given the end state and must find the start, which is exactly the trigger for Work Backwards: undo the last move first. The flip-count pattern (7 flips behave like 1 flip) simplifies the undo, and a diagram lets us draw each reversed step on the grid.
1STEP 1

Simplify the 7 upward flips

Flips cancel in pairs and 7 = 2×3 + 1, so 7 upward flips have the same effect as a single upward flip.

7 = 2 × 3 + 1
2STEP 2

Undo the last move first: turn back 90 degrees counterclockwise

Reverse the last move: turn the shown numeral-4 figure 90 degrees counterclockwise.

undo 90° CW = 90° CCW
3STEP 3

Undo the flips: flip upward once

A flip is its own undo, so flip the figure upward once. The result is the original shape.

4STEP 4

Draw the original

On the shown figure, turn it 90 degrees counterclockwise, then flip it upward once; draw that on the empty left grid.

Answer
The original shape is obtained by turning the shown figure 90 degrees counterclockwise and then flipping it upward once. Drawing those two reversed moves on the left grid gives the original shape.
Applying the original moves (flip up 7 times = flip up once, then turn 90 degrees CW) to our reconstructed shape returns the shown numeral-4 figure, confirming the work-backwards steps are consistent.
Takeaway

To go back to the start, undo the moves in reverse: turn it back the other way, then flip it once - reversing moves is just Grade 4 flip-and-turn thinking!

  • Simplify the 7 upward flips
  • Undo the last move first: turn back 90 degrees counterclockwise
  • Undo the flips: flip upward once
  • Draw the original
Where next?
Another one like thissuggested

▶ Practice — 8 problems