G5_AlgebraLesson2

Representing More Complex Situations Using Algebra

MathUp - Grade 5

Today you will:
Write equations to represent situations reflecting a range of contexts.

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​Learning Goal:
Recognize when and how situations can be represented by equations.

Match

Match the items in this flyer with an equation that shows the calculation of the cost.

• $20 each. 4 headphones

• $6 each. 12 markers

• $9 each. 6 balls

• $10 each. 5 boards

4 x 20 = 80

72 = 12 x 6

9+9+9+9+9+9=54

50 / 5 = 10

• 4 x 20 = 80

• 72 = 12 x 6

• 9+9+9+9+9+9=54

• 50 / 5 = 10

Match

Math algebraic equations with their respective situation

• 5m + 4n = 89

• 3x + 2y = 30

• 7a - 2b = 50

• 4c + 5d = 100

• 6p - 3q = 12

Buy 5 chessboards and 4 markers for $ 89

Buy 3 notebooks and 2 pens for $30

Selling 7 apples and buying 2 oranges

Collect 4 tickets and 5 drinks for $100

Gaining 6 points and losing 3 tokens

• Buy 5 chessboards and 4 markers for $ 89

• Buy 3 notebooks and 2 pens for $30

• Selling 7 apples and buying 2 oranges

• Collect 4 tickets and 5 drinks for $100

• Gaining 6 points and losing 3 tokens

You can use equations with one or more variables to describe real-life situations.

You can use the same equation to describe different situations.

In an algebra equation, there are constants, whose values don't change, and variables. In many equations, the values of variables can change.

​A way to describe mathematical relationships using symbols (variables)

Algebra:

Known value in an equation that does not change;
in 3 + a = b,
3 is a constant

​​Constant:

​Letter, shape, or other symbol that stands for a number; in the equation 3 + a = 12,
a is a variable

​​Variable:

Multiple Choice

Which equation shows that the total price of 2 identical items is $30?

• 2 + n = 30

• 2n = 30

• 30 − n = 2

• 2 × 30 = n

Open Ended

Describe a situation that this equation could represent.

3k + 6m = 90

Open Ended

Write an equation with three variables and three constants.

Mission Accomplished!