Evens & Odds from Ask Marilyn

Ask Marilyn


By Marilyn Vos Savant
As children, my siblings and I often settled a disagreement with a game called “Evens and Odds.” In this game, one side is assigned “evens” and the other is assigned “odds.” Then, on the count of three, a representative of each side reveals a number of fingers from zero to five. If the sum of the two numbers is even, the “evens” win; if the sum is odd, the “odds” win. Is this method fair? Or do the “evens” have an advantage? -Andy G., Cedar Hill, Mo.

Properties & Operations

Monday 8/22/11 Practice – Evens page 11 / Tuesday 8/23/11 Practice Odds page 11

More help with Properties;

Glossary of Properties from the Math Forum

Students also have a basic list of the properites on page 10 of their resource book.

Closure is a concept that is sometimes hard for 9th graders to grasp.  I like this explanation of the giraffe cage at the zoo…Ask Dr. Math for examples of closure.

Example for Closure we used from Questions 30-33.

T is the set of odd whole numbers.  So I ask students to list some of the numbers in this set…

T = {1, 3, 5, 7, 9, 11, 13…}

We check for closure under Addition, Subtraction, Multiplication & Division.
1 + 3 = 4  Is 4 in the set T? no, so T is not closed under Addition.

11 – 5 = 6  Is 6 in the set T?  no, so T is not closued under Subtraction

3 * 13 = 39 Is 39 in the set T? yes
5 * 11 = 55 Is 55 in the set T? yes
All students multiplied an odd * odd and ALL students got a result that was odd!
 So… T is closed under multiplication.
9 / 3 = 3 works, but if we can find at least one CounterExample
13 / 5 =  2.6, since 2.6 is not an odd whole number, T is not closed under Division.

August 15-18, 2011

Monday 8/15

Practice with CPS Remotes Entered Algebra I Pre-Test

Tuesday 8/16


  • Real Number Line/Comparing Real Numbers
  • Commutative, Associative, Distributive Properites
  • Adding Integers
  • Subtracting Integers

Cool Math online resources for Properties

Wednesday 8/17

  • Discuss Questions from Real Numbers Review
  • Automaticity Test
  • Unit 1 Pre-Test (CPS) and set Goals

Thursday 8/18

  • I can classify and compare real numbers.
  • Notes/Examples (video lesson)
  • Assign:  pages 4 & 5
  • Check HW & Target Quiz Friday

Friday 8/19

Operations with Real Numbers / Using Graphing Calculators

Learning keystrokes/menus/etc. of TI-84+needed to perform calculations.