Dyslexia: Geometric Sequences from the gr9 Math curriculum in Ontario

For Parent

A Guide to Navigating Geometric Sequences for 14 Year Olds with Dyslexia

Geometric Sequences are an important concept to learn in Grade 9 Math in Ontario. Simply put, it is an equation, often represented as an ‘arithmetic sequence’ or progression that uses factors, or multipliers in order to represent the increase or decrease in terms of a sequence. The equation for this is an = ar^(n-1), where ‘a’ being the first term and ‘r’ being the common ratio (which is the amount of increase). An example of this might be 1,2,4,8…. which is a progression that doubles while counting up, so the multiplier would be 2.

Key Challenges and Strategies for 14 Year Olds with Dyslexia

Issue 1: Difficulty with Examining Patterns:
Understanding the patterns in Geometric Sequences can be a challenge for students with Dyslexia due to difficulty with visual patterns and understanding the more abstract aspects of math. To help the student understand these patterns, it may help to introduce physical models (or objects) to represent the concept and the related pattern. For example, the student could use tokens or Unifix cubes to represent the different items in the sequence, and use them to help them understand the pattern.

Issue 2: Difficulty with Visualizing the Equation:
Similarly, visualizing the equation for a Geometric Sequence (an = ar^(n-1)) may be difficult for some students with Dyslexia. To help illustrate this, a student may use a graphing calculator to visualize the equation. Or, they could draw a graph to represent the equation, or even construct a table of terms, and fill in each consecutive line arithmetically.

Issue 3: Difficulty with Memorization of Concepts and Rules:
Dyslexia can make it challenging for students to memorize concepts and rules. To help a student remember the concept and equation of a Geometric Sequences, they could create a ‘memory palace’, or an imaginative place in their head to store the information. For example, if the student can associate a picture of a series of stairs with the equation and the concept, they could easily recall it when needed.

At a Glance: Geometric Sequences

Equation: an = ar^(n-1)
Sample Question: Find the next number in the sequence 41, 47, 53, ____?
Answer: 59 (The common ratio is 6, so 59 is the next number)

For Youth

A geometric sequence is a special kind of math pattern that follows a rule. This rule will create an equation for the sequence so that we can determine a pattern. To help you as a 14 year old with Dyslexia, let’s break it down.

The equation for a geometric sequence starts with a1 which stands for the first number in the sequence. Then we multiply that number by r. R stands for the common ratio of the sequence and r will never change throughout the sequence. The common ratio is the number that each number will be multiplied by to get the next number in the sequence.

For example, if our first number is 6 and our common ratio is 2 the equation for the sequence will be 6, 12, 24, 48, etc.

6 x 2 = 12

12 x 2 = 24

24 x 2 = 48

Once we understand the equation, it is much easier to tackle the pattern. Draw a table first that has two columns and however many rows needed for however many numbers you need to find. In the first column, write down your equation starting with the first number. In the second column, write down the answer that the result of the equation.

This will help you see the pattern and recognize it. You can also draw a picture with arrows connecting the numbers to help you trace the pattern. Try to visualize the pattern and practice writing equations like this to make them stick in your head.

You can do this. With practice and lots of patience, you will be able to do this. Be patient and have faith in yourself. Don’t give up.