Common Core · High school

HSN-VM.C.9

High school — Understand that, unlike multiplication of numbers, matrix multiplication for square matrices is not commutative, but that it is still associative and distributive.

A note on this mapping: HSN-VM.C.9 is a (+) standard — beyond the college- and career-ready threshold, i.e. precalculus rather than Algebra II.

The skill that covers it

Matrix OperationsArithmetic on rectangles of numbers: add and scale matrices, multiply them row by column, work out which products are even defined and what size they come out, take a transpose, recognise a symmetric matrix and the identity, and see for yourself that AB and BA are usually different.Read the lesson →

What a student should be able to do

Add matrices, multiply one by a scalar, and take a transpose.
Multiply two matrices, and give a single entry of a product without computing the rest.
Decide whether a product is defined and what size it is.
Recognise the identity and a symmetric matrix, and show that matrix multiplication is not commutative.

Every Common Core code covered by Math Vale