Reasoning with even and odd numbers 9/12/2011

1. Reasoning with even and odd numbers9/12/2011

2. Task: • In groups you will creating a poster about one way to reason with even and odd numbers. • You will receive a fact sheet to review, and summarize it using words, diagrams, models etc. to explain it. • These will be presented to the class, and will help them understand some basic rules we can follow to reason with even and odd numbers.

3. Even Numbers (Addition) • The sum of two even numbers is even! • Example: 2+2=4 • 24+12=36 • 6+8=14

4. Odd numbers (Addition) • Made from an even number plus one. So when you ad two odd numbers you get the sum of two even numbers. • Example: 5= 4+1 and 3=2+1 • So 5+3= 4+1+2+1 • +4+2+1+1 • =8

5. Multiplication • For multiplication: • Odd times odd = odd • Even times odd=even

6. Lets do some practice! • Without doing the actual addition/multiplication, are the following sums odd or even? • 203+512 • 934+116 • 199+0 • 59 x 45 • 120 x 56 • 59 x 0