1.1 Patterns and Expressions• Look at the figures from left to right. What is the

pattern? What would the next figure in the pattern look like?

• The pattern shows regular polygons with the number of sides increasing by one.

• The last figure shown above has six sides, so the next figure would have seven sides.

• The next figure in the pattern is a heptagon.

Variables and Expressions• A mathematical quantity is anything that can be

measured or counted.

• Quantities whose values do not change are called constants.

• Quantities whose values change or vary are called variable quantities.

Expressing a Pattern with Algebra• How many toothpicks are in the 20th figure? What is an

expression that describes the number of toothpicks in the nth figure?

• Pattern: Multiply the figure number by 4 to get the number of toothpicks.

• So, 20(4) = 80. There are 80 toothpicks in the 20th figure.

• Therefore, there are 4n toothpicks in the nth figure.

More Practice!!!!!

• Homework – Textbook p. 7 – 8 #8 – 24.