# Question Video: Adding Two 1 × 3 Matrices Mathematics

Find [1, 2, −1] + [2, 8, 2].

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### Video Transcript

Find the matrix one, two, negative one plus the matrix two, eight, two.

The first thing to note is that when we’re adding matrices, they must be of the same order. So therefore, in our question, this is gonna work because they’re both one-by-three matrices. What this means is they’ve got one row and three columns. So we’ve got one row and three columns in both of our matrices because we’ve got three different elements in each of them.

It’s important to point this out because there is a common error to call it a three-by-one matrix. But a three-by-one matrix would have this kind of vertical look to it. So you’d have your one column but three rows in essence.

Okay, so now let’s calculate what our matrix answer is going to be. So if we’re gonna add the matrices one, two, negative one and two, eight, two, then what we do is we add the corresponding elements together. So our new matrix will have the elements that are made up of one add two, two add eight, and negative one add two. And as I already said, we got this from adding the corresponding elements.

Okay, great, so now let’s see what matrix is formed. Well, if we do this, then the one-by-three matrix answer that we’re gonna get is the matrix three, 10, one.