4 mistakes learners make with rotation and position, each one named and explained.
Count the steps one at a time, and say where you are after each one.
Two faces that share an edge on the net are called opposite on the cube.
On the flat net the two faces sit close together, and closeness feels like opposite once folded.
Question. On a cross shaped net, which face ends up opposite the top square of the column?
A common answer. The square next to it, because they touch
The answer. The square two steps away along the column
Why. Faces that share an edge on the net still share an edge on the cube. Opposite faces sit two apart along a strip of the net.
On a strip of the net, opposite faces are two apart, never next door.
A count of vertices is given when edges were asked for.
The three counts live together in the same fact, and the question's exact word slips.
Question. How many edges has a triangular prism?
A common answer. 6, which is its number of vertices
The answer. 9
Why. Edges are the lines where two faces meet: three around each triangle and three joining them. Vertices are the corners, and there are six of those.
Underline the word faces, edges or vertices in the question before counting.
A position after three moves is given as the position after two or four.
Counting moves and counting positions are easy to confuse when both are small numbers.
Question. A dot starts top-left and moves one corner clockwise, three times
A common answer. top-right, after one move
The answer. bottom-left, after three
Why. Top-left goes to top-right, then bottom-right, then bottom-left.
Say each position out loud as you move. Counting under your breath loses a step.
After a reflection or rotation, the untouched original is chosen.
The original arrangement is the picture already in your head, so it feels like the answer.
Question. A flag with its pole on the left is reflected in a vertical mirror. What does it look like?
A common answer. Pole still on the left
The answer. Pole on the right, flag pointing left
Why. A mirror swaps left and right. If nothing moved, no reflection has happened.
After any turn or flip, something must look different. Find what moved.
WAJD spots these patterns in your child's answers and names the one behind their wrong answers, instead of just marking them wrong.