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Grade 11 · Math · Algebra 2

11th grade Matrices: size, entries, add, subtract and scalar multiples worksheet

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Matrices: size, entries, add, subtract and scalar multiples

Grade 11 Math Worksheet

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Circle the best answer, or write your answer on the line.

  1. Row 1: -3, 9; row 2: 8, 5. Matrix B: row 1: -5, -5; row 2: -9, 6. Milo subtracts matrix B from matrix A. What is the entry in row 1, column 2 of A − B?

  2. Read this first

    Matrix A

    Row 1: -4, 7, 2; row 2: -6, 4, 4; row 3: -9, 7, 4. Matrix B: row 1: 1, -8, -5; row 2: 1, 1, -6; row 3: -4, -6, -3.

  3. Noah finds A − B one cell at a time. What is the entry in row 2, column 3 of A − B?

  4. Row 1: -6, -5; row 2: 12, -8. Matrix B: row 1: 5, 5; row 2: -3, 7. Pia checks row 2, column 1 of A − B. What is that entry?

  5. Row 1: 4, 1, 4; row 2: 1, 4, 1. Matrix A lists the cups of nuts, raisins and pretzels in Tala's two trail mixes. Tala makes 3 batches of each. Which matrix is 3A?

    • rows (7, 4, 7) and (4, 7, 4)
    • rows (12, 1, 4) and (1, 4, 1), one entry scaled
    • rows (12, 3, 12) and (3, 12, 3)

  6. Row 1: 2, 7; row 2: 6, 5. Matrix A gives the spoons of each paint in Zee's two color mixes. Zee doubles both mixes. Which matrix is 2A?

    • rows (4, 7) and (6, 5)
    • rows (4, 14) and (12, 10)
    • rows (4, 9) and (8, 7), scalar added

  7. Row 1: -6, -3; row 2: 2, 2. Bo multiplies every entry of matrix A by 4. Which matrix is 4A?

    • rows (-24, -3) and (2, 2)
    • rows (-24, -12) and (8, 8)
    • rows (-2, 1) and (6, 6)
    • rows (24, 12) and (8, 8)

  8. Row 1: 8, 7; row 2: 8, 2. Matrix B: row 1: -5, -2, -4; row 2: -1, 6, -3. Noah's worksheet asks for A + B. What is A + B?

    • Undefined: A and B are different sizes
    • rows (3, 5, -4) and (7, 8, -3), missing entry taken as zero
    • rows (3, 5) and (7, 8)

  9. Matrix A

    Row 1: 3, 6, 7; row 2: 1, 2, 1. Matrix B: row 1: 2, -5, 8; row 2: -8, 6, 9.

  10. Pia tries to add matrices A and B. What is A + B?

    • rows (5, 11, 15) and (9, 8, 10)
    • rows (5, 1, 15) and (-7, 8, 10)
    • Undefined: A and B are different sizes

  11. Matrix A

    Row 1: 8, -7; row 2: 6, -3; row 3: 8, 6. Matrix B: row 1: -5, -6; row 2: -4, 1.

  12. What is A + B for the two matrices on Ren's card?

    • Undefined: A and B are different sizes
    • rows (3, -13) and (2, -2)
    • rows (3, -13), (2, -2) and (8, 6)

  13. Matrix A

    Row 1: -1, 9; row 2: -1, 2; row 3: -4, -8. Matrix B: row 1: -1, 6; row 2: -8, -1; row 3: 6, 7.

  14. Tala checks the sizes first, then adds. What is A + B?

    • rows (0, 15), (7, 3) and (2, -1)
    • rows (-2, 15), (-9, 1) and (2, -1)
    • Undefined: A and B are different sizes
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11th grade Matrices: size, entries, add, subtract and scalar multiples worksheet – printable
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About this worksheet

Matrices: size, entries, adding, subtracting and scalar multiples. Every version has 10 questions, and the answer key prints on the second page.

What your child will learn

  • I can give a matrix's size as rows × columns and read the entry in any row and column.
  • I can turn a table of data into a matrix, and add or subtract matrices of the same size.
  • I can multiply a matrix by a number, and say when two matrices cannot be added.

Standard: N-VM.C.6 (+), N-VM.C.7 (+), N-VM.C.8 (+)

Words to know

matrix: A number table in brackets: rows across, columns down.

size: Rows × columns: 2 × 3 means 2 rows and 3 columns.

entry: One number in a matrix, named by its row and column.

scalar: A plain number that multiplies every entry, like the 3 in 3A.

undefined: Cannot be done: matrices of different sizes do not add.

Common mistakes

Mixed up rows and columns. Rows go across and are named first; ask your child to point to row 2, then column 3.

Counted every number instead of giving rows by columns.

Lost a minus sign when adding or subtracting a negative number.

What to say

Ask: how many rows, and how many numbers in each row?

Ask: what is 4 + (−6)? And 4 − (−6)?

Questions parents ask

What is the most common mistake with matrices: size, entries, add, subtract and scalar multiples?

Mixed up rows and columns. Rows go across and are named first; ask your child to point to row 2, then column 3.

Are these 11th grade math worksheets free to print?

Yes. All 6 printable versions at each level are free to print, with the answer key, and no account is needed.

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