8th Grade Math

Eighth Graders have reached the exciting part their curriculum — learning about and comparing different algebraic relationships, modeling different patterns of growth, and connecting them to real life situations.

Beginning the year by reviewing Linear equations (straight lines), they have gathered the skills needed to move into examining Exponential Relationships (earning interest on a bank account, mold growing on bread), Inverse Relationships (see-saws), and now Quadratic Relationships (throwing the ball up and watching it land).

Its amazing to watch how the eighth graders can connect their skills to problem solving and move forward mathematically so fast. Problems they are solving include:

A)  Combine and simplify these expressions using addition and subtraction:

  1. 2t + 12u – 21t – 11u =
  2. 5d3 + 6d2 – 9d + 18d3 – 4d2 – 21 =

B)  Find the growth factor and the growth rate. Write the equation, too.

Year Kangaroos
1997 1200
1998 2640
1999 5808
2000 12777.6

Growth Factor: ___________

Growth Rate: _____________

Equation: _________________________


 C)   Daniel and Ellen are both trying to earn money to buy a new laptop. Each student is following a different savings plan.


Week Daniel’s Plan Ellen’s Plan
0 $30 $1
1 $50 $2
2 $70 $4
3 $90 $8
4 $110 $16

a)     Complete the table.


b)    Decide whether each plan is linear or exponential. Explain your reasoning! Answer in a complete sentence.


c)     For each plan write an equation that represents the number of weeks, W and the amount of money saved, M.


Daniel’s Plan:                                                                        Ellen’s Plan:



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