Topic explanation

Standard explanation

Walk along the row and down the column, multiply pairs, add. One entry at a time. Show the sum on its own lines in an exam.

Key points

• dot product of row and col
• A columns = B rows
• AB != BA in general
• row against column
• ROW TIMES COLUMN: Walk along the row and down the column, multiply pairs, add. One entry at a time. Show the sum on it
• ROW TIMES COLUMN: Walk along the row and down the column, multiply pairs, add.
• WHAT — ROW TIMES COLUMN: Walk along the row and down the column, multiply pairs, add. One entry at a time. Show the sum on it
• WHY — Why it matters: This rule is a separate learning unit inside matrix multiplication. It can be defined, applied, and

Labelled diagram