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Secondary 2 · Mathematics
Algebra · Algebra

Operations with Monomials

Before you start, make sure you know: Properties of exponents (Secondary Year 1)
Before you start, make sure you know: Monomials and operations with monomials (Secondary Year 1)

In a racing video game, each gold coin is worth $5x$ points and each silver coin is worth $2x$ points. If you collect 4 gold coins and 6 silver coins, how many points do you earn? To find out, you need to multiply and add monomials with ease.

Parts of a monomial

A monomial is the product of a number and one or more letters with natural-number exponents. Its parts are:

  • The coefficient: the number that multiplies. If you can't see one, it is 1 (in $-a^2b$ the coefficient is $-1$).

  • The literal part: the letters with their exponents.

  • The degree: the sum of the exponents of the literal part. A number by itself, like $-5$, has degree 0.

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To understand how mathematical expressions are constructed, it is essential to know the parts of a monomial. Complete the requested information for each of the following…

To understand how mathematical expressions are constructed, it is essential to know the parts of a monomial. Complete the requested information for each of the following monomials:

  1. a) $7x^{3}$
  2. b) $-a^{2}b$
  3. c) $\frac{1}{2}x^{4}y^{2}$
  4. d) $-5$

For each one, state:

  • The coefficient.

  • The literal part.

  • The degree of the monomial.

Solve

Adding and subtracting like monomials

Two monomials are like monomials if they have exactly the same literal part. Only like monomials can be added or subtracted: you operate on the coefficients and the literal part stays the same. It's like counting objects of the same kind: 3 tacos + 2 tacos = 5 tacos, but 3 tacos + 2 sodas can't be combined.

$$3ab - 5ab + ab = (3 - 5 + 1)ab = -ab$$ Diagram of adding like monomials 3ab − 5ab + ab by operating on the coefficients 3 − 5 + 1 to get −ab. 3ab − 5ab + ab sum of coefficients = −ab (3 − 5 + 1 = −1)
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In algebra, we can only add or subtract "like terms". Identify which of the following monomials are like terms and group them: $5x^{2}$, $-3x$, $\frac{1}{4}x^{2}$, $7y$,…

In algebra, we can only add or subtract "like terms". Identify which of the following monomials are like terms and group them:

$5x^{2}$, $-3x$, $\frac{1}{4}x^{2}$, $7y$, $x$, $-x^{2}$, $12x$, $2y$

Solve
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Simplify the following expressions by adding and subtracting like monomials: a) $5a + 3a - 2a$ b) $4x^{2} - x^{2} + 7x^{2}$ c) $3ab - 5ab + ab$ d) $x + x + x + x$

Simplify the following expressions by adding and subtracting like monomials:

  1. a) $5a + 3a - 2a$
  2. b) $4x^{2} - x^{2} + 7x^{2}$
  3. c) $3ab - 5ab + ab$
  4. d) $x + x + x + x$
Solve
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Fully simplify the following algebraic expression by grouping like monomials: $9x^3 - 5x^2 + 4x - 2x^3 + 7x^2 - x + 10$

Fully simplify the following algebraic expression by grouping like monomials:

$9x^3 - 5x^2 + 4x - 2x^3 + 7x^2 - x + 10$

Solve

Multiplying monomials

$$(3x^2)(5x^4) = (3 \cdot 5)(x^2 \cdot x^4) = 15x^6$$ Rectangle with base 5x and height 3x whose area is 15x² when both monomials are multiplied. 5x (base) 3x (height) Area = 3x · 5x = 15x²
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Calculate the product of the following monomials. Remember to multiply the coefficients together and add the exponents of identical letters: a)…

Calculate the product of the following monomials. Remember to multiply the coefficients together and add the exponents of identical letters:

  1. a) $(3x^{2}) \times (5x^{4})$
  2. b) $(-2a^{3}) \times (4a)$
  3. c) $(\frac{1}{2}x) \times (6x^{2})$
  4. d) $(-x^{2}) \times (-x^{3})$
Solve
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Calculate the result of the following monomial multiplications and simplify the literal part using index laws: a) $(4a^2b) \times (-3ab^3)$ b)…

Calculate the result of the following monomial multiplications and simplify the literal part using index laws:

  1. a) $(4a^2b) \times (-3ab^3)$
  1. b) $(\frac{1}{2}x^4) \times (6x^2)$
  1. c) $(-2z^3) \times (-5z^2) \times z$
Solve

Dividing monomials

$$\frac{15x^3y^2}{3x^2y} = \frac{15}{3}\,x^{3-2}y^{2-1} = 5xy$$
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Perform the following divisions of monomials. Remember to divide the coefficients and subtract the exponents of the letters: a) $(12x^{5}) : (3x^{2})$ b)…

Perform the following divisions of monomials. Remember to divide the coefficients and subtract the exponents of the letters:

  1. a) $(12x^{5}) : (3x^{2})$
  2. b) $(-10a^{4}) : (5a^{3})$
  3. c) $(15x^{3}y^{2}) : (3x^{2}y)$
  4. d) $(4x^{2}) : (2x^{2})$
Solve
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Simplify the following monomial quotients. Express the result as a single monomial where possible: a) $\frac{20x^6}{5x^2}$ b) $(-12a^3b^2) : (3a^2b^2)$ c)…

Simplify the following monomial quotients. Express the result as a single monomial where possible:

  1. a) $\frac{20x^6}{5x^2}$
  1. b) $(-12a^3b^2) : (3a^2b^2)$
  1. c) $\frac{15m^4n^2}{10m^2}$
Solve

Power of a monomial

$$(2x^3)^2 = 2^2 \cdot (x^3)^2 = 4x^6$$
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Calculate the power of these monomials. Do not forget to raise both the coefficient and the literal part to the indicated exponent: a) $(2x^{3})^{2}$ b) $(-3a^{2})^{2}$…

Calculate the power of these monomials. Do not forget to raise both the coefficient and the literal part to the indicated exponent:

  1. a) $(2x^{3})^{2}$
  2. b) $(-3a^{2})^{2}$
  3. c) $(x^{4})^{3}$
  4. d) $(-2x)^{3}$
Solve
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Work out the following powers of monomials. Remember that the exponent affects both the coefficient and each of the variables in the literal part: a) $(-3x^4)^2$ b)…

Work out the following powers of monomials. Remember that the exponent affects both the coefficient and each of the variables in the literal part:

  1. a) $(-3x^4)^2$
  1. b) $(2a^2b^3)^4$
  1. c) $(-\frac{1}{2}m^5)^3$
Solve

Combined operations

The usual order of operations applies: first parentheses and powers, then multiplications and divisions, and finally additions and subtractions (only of like monomials).

When a monomial multiplies a polynomial, we use the distributive property: multiply by each term and then combine the like terms.

It's also useful for factoring out the common factor: take the GCF of the coefficients and each common letter with its smallest exponent. In $12x^3 + 18x^2$ the GCF of 12 and 18 is 6 and the common letter $x$ has smallest exponent 2, so we get $6x^2(2x + 3)$.

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Solve the following combined operations with monomials, respecting the order of operations: a) $5x^2 \times 2x + 12x^4 : 3x$ b) $3ab \times (2a^2b) - (5a^3b^2)$ c)…

Solve the following combined operations with monomials, respecting the order of operations:

  1. a) $5x^2 \times 2x + 12x^4 : 3x$
  1. b) $3ab \times (2a^2b) - (5a^3b^2)$
  1. c) $(2n^3)^2 - 5n^6 + n^2 \times n^4$
Solve
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Work out the following combined operation with monomials, fully simplifying the result. Pay special attention to the order of operations and power rules: $$…

Work out the following combined operation with monomials, fully simplifying the result. Pay special attention to the order of operations and power rules:

$$ \frac{2}{3}x^2 \times (-3x^3)^2 - 5x^5 \times (2x^3) + \frac{16x^{10}}{2x^2} $$
Solve
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Simplify the following expression by applying the distributive property and combining the resulting like monomials: $$ -3ab^2 \times (2a^2 - 5ab + b^2) - 2a^2b \times…

Simplify the following expression by applying the distributive property and combining the resulting like monomials:

$$ -3ab^2 \times (2a^2 - 5ab + b^2) - 2a^2b \times (4ab - a) $$
Solve

Unknown monomials and common factor

To find a missing monomial, use the inverse operation: if $A \cdot M = B$, then $M = B : A$.

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Find the unknown monomials $M$ and $N$ that make the following equalities true: a) $ (-4x^3y^2) \times M = 20x^7y^5 $ b) $ \frac{N}{-3ab} = 6a^2b^3 $ c)…

Find the unknown monomials $M$ and $N$ that make the following equalities true:

  1. a) $ (-4x^3y^2) \times M = 20x^7y^5 $
  1. b) $ \frac{N}{-3ab} = 6a^2b^3 $
  1. c) $ (2x^2)^3 : M = -4x $
Solve
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In a strategy video game, a battalion's energy is calculated by multiplying its attack level by its defence level, divided by its fatigue. Given that: Attack:…

In a strategy video game, a battalion's energy is calculated by multiplying its attack level by its defence level, divided by its fatigue. Given that:

  • Attack: $ 12a^2b^3 $

  • Defence: $ 5a^3b $

  • Fatigue: $ 10ab^2 $

Express the total energy of the battalion as a single monomial and determine its degree.

Solve
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Factorise out the highest common factor in the following algebraic expression. Remember to extract both the highest common factor of the coefficients and the common…

Factorise out the highest common factor in the following algebraic expression. Remember to extract both the highest common factor of the coefficients and the common variables with their lowest exponent:

$$ 24x^5y^4z^2 - 36x^3y^6z^3 + 12x^2y^4z^5 $$
Solve
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Calculate the value of the resulting monomial at the top of this "product pyramid", where each brick is the product of multiplying the two monomials directly below it:

Calculate the value of the resulting monomial at the top of this "product pyramid", where each brick is the product of multiplying the two monomials directly below it:

× × × −2x 3x² -x³ A B ¿?
Solve

Perimeters, areas, and volumes

The perimeter of a figure is the sum of the lengths of its sides; the area of a rectangle is base times height, and the volume of a cube with edge $a$ is $a^3$.

Rectangle with base 3x and height x illustrating the calculation of its area by multiplying and its perimeter by adding. 3x x Area = 3x² Perimeter = 3x+x+3x+x = 8x

For a shaded region (such as a square with side $4x$ with another square of side $x$ cut out), you subtract: total area minus the area removed.

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Find the algebraic expression representing the perimeter of the following rectangular plot for a school garden. Once you have the expression, fully simplify it by…

Find the algebraic expression representing the perimeter of the following rectangular plot for a school garden. Once you have the expression, fully simplify it by combining like terms.

3x x
Solve
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Find the simplified algebraic expression representing the perimeter of the following plot designated for a play area in a park:

Find the simplified algebraic expression representing the perimeter of the following plot designated for a play area in a park:

5x x 2x 2x 2x 2x
Solve
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Find the expression representing the area of the shaded region in the following figure, knowing that the side of the outer square measures $4x$ and the side of the inner…

Find the expression representing the area of the shaded region in the following figure, knowing that the side of the outer square measures $4x$ and the side of the inner white square measures $x$:

4x x
Solve
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A design company manufactures aluminum frames for tablet screens. The design follows the proportions shown in the following figure, where all measurements are expressed…

A design company manufactures aluminum frames for tablet screens. The design follows the proportions shown in the following figure, where all measurements are expressed in terms of a variable $x$. Find the monomial representing the total surface area of the frame (the shaded region).

Area = ? 6x 4x 4x 2x
Solve
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Calculate the monomial representing the volume of a 3D shape formed by joining 5 identical cubes, where the edge of each cube measures $ \frac{2}{3}x^2 $ meters. Express…

Calculate the monomial representing the volume of a 3D shape formed by joining 5 identical cubes, where the edge of each cube measures $ \frac{2}{3}x^2 $ meters. Express the final result in simplified form.

2 3 x² × 5
Solve

Problems with monomials

To translate a problem, identify what is multiplied (amounts per group) and what is added (parts of the same kind).

Back to the beginning: the 4 gold coins are worth $4 \cdot 5x = 20x$ points and the 6 silver coins are worth $6 \cdot 2x = 12x$. They are like monomials, so you add $20x + 12x = 32x$ points.

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In a racing video game, for each gold coin collected you get $5x$ points and for each silver coin you get $2x$ points. If in a game a player has collected 4 gold coins…

In a racing video game, for each gold coin collected you get $5x$ points and for each silver coin you get $2x$ points.

If in a game a player has collected 4 gold coins and 6 silver coins:

  1. a) Write the monomial representing the total points from the gold coins.
  2. b) Write the monomial representing the total points from the silver coins.
  3. c) Add both monomials to find the total points for the game.

You can do it on paper and send a photo with your answer.

Solve
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In a tree-planting campaign, each volunteer plants $3x$ trees in the morning and $2x$ trees in the afternoon. If there are a total of $y$ volunteers, write the…

In a tree-planting campaign, each volunteer plants $3x$ trees in the morning and $2x$ trees in the afternoon. If there are a total of $y$ volunteers, write the simplified algebraic expression representing:

  1. a) The total number of trees planted by a single volunteer in one day.
  1. b) The total number of trees planted by all volunteers in a week (7 days).
Solve

Summary

See all the exercises in this section